【Android】App支援多種不同螢幕規格的方式

官方文件及網站找到的資料, 寫的很好, 但android 機型實在太多了, 有些要實機測一下, 才不會失真


 http://magiclen.org/android-screen/

【Android】使用AsyncTask下載檔案

簡單運用, 記得改一些參數



    private class downloadPost extends AsyncTask<String, Integer, String> {
        private Context context;
        private ProgressDialog pd;
        private String strUrl;

        public downloadPost(Context context, String url) {
            this.context = context;
            strUrl = url;
        }

        @Override
        protected void onPreExecute() {
            pd = new ProgressDialog(context);
            pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            pd.setMessage("下載中 ...");
            pd.setCancelable(false);
            pd.show();


        }

        @Override
        protected String doInBackground(String... params) {


            downloadFile(strUrl);


            return null;
        }


        // run Progress
        @Override
        protected void onProgressUpdate(Integer... values) {

            super.onProgressUpdate(values);

            if (pv.DEBUG_MODE) System.out.println(TAG + "values:" + values[0]);

            pd.setProgress(values[0]); // update Progress

        }


        // cancel upload
        @Override
        protected void onCancelled() {

            if (pv.DEBUG_MODE) System.out.println(TAG + "onCancelled");

        }

        @Override
        protected void onPostExecute(String result) {
            if (pv.DEBUG_MODE) {
                System.out.println("result onPostExecute : " + result);
            }


            player = new MusicPlayer(saveFileName, skbProgress);

            pd.dismiss();

            Toast.makeText(LessonContentActivity.this, "下載完成", Toast.LENGTH_SHORT).show();
        }


        private void downloadFile(String fileUrl) {
            try {
                //set the download URL, a url that points to a file on the internet
                //this is the file to be downloaded
                URL url = new URL(fileUrl);

                //create the new connection
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                //set up some things on the connection
                urlConnection.setRequestMethod("GET");
                urlConnection.setDoOutput(true);

                //and connect!
                urlConnection.connect();
                //set the path where we want to save the file
                //in this case, going to save it on the root directory of the
                //sd card.
                File SDCardRoot = new File(Environment.getExternalStorageDirectory() + "/easylisten/" + courseId + "/");
                if (!SDCardRoot.exists()) {
                    SDCardRoot.mkdirs();
                }
                //create a new file, specifying the path, and the filename
                //which we want to save the file as.

                //file Name : i.am.a.file.jpg || hahaha
                //fileUrl : http://solvefzt2.fzt.cc/.../i.am.a.file.jpg || hahaha.png
                String realFileName = fileUrl.split("/")[fileUrl.split("/").length - 1];
                String fileMime = realFileName.split("\\.")[realFileName.split("\\.").length - 1];

                if (pv.DEBUG_MODE) {

                    System.out.println(TAG + "realFileName:" + realFileName);
                    System.out.println(TAG + "fileMime:" + fileMime);
                }

                File file = null;

                file = new File(SDCardRoot, realFileName);

                if (pv.DEBUG_MODE) {
                    System.out.println(TAG + "file.isFile SDCardRoot,realFileName:" + SDCardRoot + "/" + realFileName);
                }
                saveFileName = SDCardRoot + "/" + realFileName;

                if (file.isFile()) {

                    return;
                }

                //this will be used to write the downloaded data into the file we created
                FileOutputStream fileOutput = new FileOutputStream(file);

                //this will be used in reading the data from the internet
                InputStream inputStream = urlConnection.getInputStream();


                //this is the total size of the file
                totalSize = urlConnection.getContentLength();


                //variable to store total downloaded bytes
                int downloadedSize = 0;

                //create a buffer...
                byte[] buffer = new byte[1024];
                int bufferLength = 0; //used to store a temporary size of the buffer

                //now, read through the input buffer and write the contents to the file
                while ((bufferLength = inputStream.read(buffer)) > 0) {
                    //add the data in the buffer to the file in the file output stream (the file on the sd card
                    fileOutput.write(buffer, 0, bufferLength);
                    //add up the size so we know how much is downloaded
                    downloadedSize += bufferLength;

                    //this is where you would do something to report the Progress
                    publishProgress((int) ((downloadedSize / totalSize) * 100));

                    fileOutput.flush();
                }
                //close the output stream when done
                fileOutput.close();


                //catch some possible errors...
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

【Android】HttpURLConnection Get 方法

    public static String excuteGet(String targetURL, String urlParameters) {


        URL url;
        HttpURLConnection conn = null;
        try {
            //Create connection
            url = new URL(targetURL);
            conn = (HttpURLConnection) url.openConnection();

            // 進行連接，但是實際上get request要在下一句的connection.getInputStream()函數中才會真正發到伺服器
            conn.connect();

            //Get Response  ,  取得輸入流，並使用Reader讀取
            InputStream is = conn.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            String line;
            StringBuilder response = new StringBuilder();
            while ((line = reader.readLine()) != null) {
                response.append(line);
                response.append('\r');
            }
            reader.close();

            return response.toString();

        } catch (Exception e) {

            e.printStackTrace();
            return null;

        } finally {

            if (conn != null) {
                conn.disconnect();
            }
        }
    }

【Android】HttpURLConnection Post 方法

    public static String excutePost(String targetURL, String urlParameters) {
        URL url;
        HttpURLConnection conn = null;


        try {
            //Create connection
            url = new URL(targetURL);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");

            conn.setRequestProperty("Content-Length", "" +
                    Integer.toString(urlParameters.getBytes().length));
            conn.setRequestProperty("Content-Language", "en-US");

            conn.setUseCaches(false);     // Post cannot use caches
            conn.setDoInput(true);        // Read from the connection. Default is true.


            // Output to the connection. Default is false, set to true because post
            // method must write something to the connection
            conn.setDoOutput(true);

            //Send request
            DataOutputStream wr = new DataOutputStream(
                    conn.getOutputStream());
            wr.writeBytes(urlParameters);
            wr.flush();
            wr.close();

            //Get Response
            InputStream is = conn.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(is));
            String line;
            StringBuilder response = new StringBuilder();
            while ((line = reader.readLine()) != null) {
                response.append(line);
                response.append('\r');
            }
            reader.close();

            return response.toString();

        } catch (Exception e) {

            e.printStackTrace();
            return null;

        } finally {

            if (conn != null) {
                conn.disconnect();
            }
        }
    }

【Android】系統簡單應用—個人GPS定位(儲存在雲端)

原始碼 GitHub : https://github.com/markcoolhu/GpsTrackingCloud.git




package hu.markcool.mygps;


import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import java.security.KeyStore;
import java.util.ArrayList;
import java.util.List;

import ssl.SSLSocketFactoryEx;

public class GpsService extends Service {

    private static final String TAG = "GpsService ";

    private LocationManager mLocationManager = null;

    // The minimum time between updates in milliseconds
    private static final int MIN_TIME_BW_UPDATES = 1000 * 30; // 1 minute

    // The minimum distance to change Updates in meters
    private static final float MIN_DISTANCE_CHANGE_FOR_UPDATES = 50f;

    private String deviceId;

    private double latitude, longitude;

    // Define a listener that responds to location updates
    private class LocationListener implements android.location.LocationListener {
        Location mLastLocation;

        public LocationListener(String provider) {
            Log.e(TAG, "LocationListener " + provider);
            mLastLocation = new Location(provider);
        }

        @Override
        public void onLocationChanged(Location location) {
            Log.e(TAG, "onLocationChanged: " + location);

//            Toast.makeText(getApplicationContext(), "Location Changed, now:" + location, Toast.LENGTH_SHORT).show();

            mLastLocation.set(location);

            if (location == null)  return;

            Location dest = new Location(location); //取得現在位置
            latitude = dest.getLatitude();
            longitude = dest.getLongitude();

            Toast.makeText(getApplicationContext(), "Location Changed, now latitude:" + latitude +
                    ", longitude:" + longitude, Toast.LENGTH_SHORT).show();

            // save cloud DB
            Thread t1=new Thread(postData);
            t1.start();

        }

        @Override
        public void onProviderDisabled(String provider) {
            Log.e(TAG, "onProviderDisabled: " + provider);
        }

        @Override
        public void onProviderEnabled(String provider) {
            Log.e(TAG, "onProviderEnabled: " + provider);
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            Log.e(TAG, "onStatusChanged: " + provider);
        }
    }

    LocationListener[] mLocationListeners = new LocationListener[]{
            new LocationListener(LocationManager.GPS_PROVIDER),
            new LocationListener(LocationManager.NETWORK_PROVIDER)
    };

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.e(TAG, "onStartCommand");
        super.onStartCommand(intent, flags, startId);
        return START_STICKY;
    }

    @Override
    public void onCreate() {

        Log.e(TAG, "onCreate");

        // get device id
        GetDeviceId gdi = new GetDeviceId();
        deviceId = gdi.getDeviceId(this);


        initializeLocationManager();
        try {
            mLocationManager.requestLocationUpdates(
                    LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES,
                    mLocationListeners[1]);
        } catch (java.lang.SecurityException ex) {
            Log.i(TAG, "fail to request location update, ignore", ex);
        } catch (IllegalArgumentException ex) {
            Log.d(TAG, "network provider does not exist, " + ex.getMessage());
        }
        try {
            mLocationManager.requestLocationUpdates(
                    LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES,
                    mLocationListeners[0]);
        } catch (java.lang.SecurityException ex) {
            Log.i(TAG, "fail to request location update, ignore", ex);
        } catch (IllegalArgumentException ex) {
            Log.d(TAG, "gps provider does not exist " + ex.getMessage());
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        Log.e(TAG, "onDestroy");

        if (mLocationManager != null) {
            for (int i = 0; i < mLocationListeners.length; i++) {
                try {
                    mLocationManager.removeUpdates(mLocationListeners[i]);
                } catch (Exception ex) {
                    Log.i(TAG, "fail to remove location listners, ignore", ex);
                }
            }
        }
    }

    private void initializeLocationManager() {

        Log.e(TAG, "initializeLocationManager");

        if (mLocationManager == null) {
            // Acquire a reference to the system Location Manager
            mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
        }
    }


    private Runnable postData = new Runnable () {
        public void run() {


            System.out.println("latitude:" + String.valueOf(latitude));
            System.out.println("longitude:" + String.valueOf(longitude));
            System.out.println("deviceId:" + deviceId);

            // params post use (not json format)
            List<NameValuePair> params = new ArrayList<>();

            params.add(new BasicNameValuePair("latitude", String.valueOf(latitude)));
            params.add(new BasicNameValuePair("longitude", String.valueOf(longitude)));
            params.add(new BasicNameValuePair("device_id", deviceId));


            htmlFormPost(params);

        }
    };

    // process html form post (not image or file post)
    private String htmlFormPost(List<NameValuePair> params) {

        String httpLink = "http://52.74.67.51/gps_tracking/gps_updata.php";

        String resultString = null;

        // Instantiate the custom HttpClient
        HttpClient httpClient = getNewHttpClient();

        // Create a new HttpClient and Post Header
        // HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(httpLink);
        HttpResponse response;

        try {

            // Bound to request Entry
            httpPost.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));

            System.out.println("httpPost :" + httpPost);

            // Execute HTTP Post Request
            response = httpClient.execute(httpPost);

            System.out.println("response code :" + response.getStatusLine().getStatusCode());

            if (response.getStatusLine().getStatusCode() == 200) {
                // get response string, JSON format data
                resultString = EntityUtils.toString(response.getEntity());

            } else {
                resultString = null;
                System.out.println("response not ok, status :" + response.getStatusLine().getStatusCode());

            }


        } catch (Exception e) {

            System.out.println("HttpPost Exception : " + e.toString());

        } finally {
            httpClient.getConnectionManager().shutdown();
        }

        System.out.println("resultString : " + resultString);

        return resultString;
    }


    // ssl process
    private HttpClient getNewHttpClient() {
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
            trustStore.load(null, null);

            SSLSocketFactory sf = new SSLSocketFactoryEx(trustStore);
            sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

            HttpParams params = new BasicHttpParams();
            HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
            HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);

            SchemeRegistry registry = new SchemeRegistry();
            registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
            registry.register(new Scheme("https", sf, 443));

            ClientConnectionManager ccm = new ThreadSafeClientConnManager(params, registry);

            return new DefaultHttpClient(ccm, params);
        } catch (Exception e) {
            return new DefaultHttpClient();
        }
    }
}

【Android】開發中關於Fragment異常的問題(java.lang.IllegalStateException: Fragment not attached to Activity)

剛好遇到這問題, 找了一下, 有個網站有寫到,

http://blog.csdn.net/walker02/article/details/7995407

 

我用到了這方法：

關於Fragment（XXFragment） not attached to Activity 異常。出現該異常，是因為Fragment的還沒有Attach到Activity時，調用了如getResource()等，需要上下文Content的函數。

 

解決方法，就是等將調用的代碼寫在OnStart（）中。

 

網上還有幾處這樣的參考：http://stackoverflow.com/questions/10919240/fragment-myfragment-not-attached-to-activity   

 

在【getResources().getString(R.string.app_name);】之前增加一個判斷isAdded(),

另外的異常解決辦法的有 http://stackoverflow.com/questions/6870325/android-compatibility-package-fragment-not-attached-to-activity

這個是針對另外一種情況下的解決方式。

【Android】攔截/遮罩返回鍵(BACK KEY)

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) { //監控/攔截/遮罩返回鍵
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_MENU) {
            //監控/攔截菜單鍵
        } else if (keyCode == KeyEvent.KEYCODE_HOME) {
            //由於Home鍵為系統鍵，此處不能捕獲，需要重寫onAttachedToWindow()
        }
        return super.onKeyDown(keyCode, event);
    }