Android 实现图片保存到本地并调用本地地址显示图片
16lz
2021-01-23
话不多说上代码
public class MainActivity extends AppCompatActivity {private Button cunn;private Button xian; private ImageView ttt;//private EditText rrr;public static final int EXTERNAL_STORAGE_REQ_CODE = 10 ;@Overrideprotected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); cunn =(Button)findViewById(R.id.cun); xian=(Button)findViewById(R.id.xians); ttt=(ImageView)findViewById(R.id.tt); // rrr=(EditText)findViewById(R.id.rr); //final Intent intent = new Intent(MainActivity.this,Download.class); final MyDownloadManager myDownloadManager = new MyDownloadManager(); //final String path= rrr.getText().toString(); final String path = "https://dss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=2534506313,1688529724&fm=26&gp=0.jpg"; //final String path1 = "https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=1328477591,2018436166&fm=26&gp=0.jpg"; //final String dirname ="/sdcard/"; //final String filename ="rr"; //final Download download = new Download(); // final dd d =new dd(); cunn.setOnClickListener(new View.OnClickListener() { @RequiresApi(api = Build.VERSION_CODES.O) @Override public void onClick(View view) { myDownloadManager.addDownloadTask(path); // try { // d.ddt(path1,dirname,filename); // } catch (IOException e) { // e.printStackTrace(); // } } }); xian.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //File file = new File(String.valueOf(myDownloadManager.getDownloadDir())); //Bitmap bm = BitmapFactory.decodeFile(myDownloadManager.getDownloadDir()+myDownloadManager.getfileName(path)); // ttt.setImageBitmap(bm); ttt.setImageURI(Uri.fromFile(new File(myDownloadManager.getDownloadDir() +"/"+ myDownloadManager.getfileName(path)))); //ttt.setImageUri(Uri.fromFile(new File("/sdcard/test.jpg"))); } }); int permission = ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // 请求权限 ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, EXTERNAL_STORAGE_REQ_CODE); }}public static String MD5(String path) { // URL url = new URL(path); //String url = path; //String path = Environment.getExternalStorageDirectory().getAbsolutePath(); //final long startTime = System.currentTimeMillis(); //String filename=url.substring(url.lastIndexOf("/") + 1); String filename ="pp.jpg"; return filename;}//
public class MyDownloadManager {public static final int EXTERNAL_STORAGE_REQ_CODE = 10 ;private static final int REQUEST_EXTERNAL_STORAGE = 1;private static String[] PERMISSIONS_STORAGE = { Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE };/** * Checks if the app has permission to write to device storage * * If the app does not has permission then the user will be prompted to * grant permissions * * @param activity */public static void verifyStoragePermissions(Activity activity) { // Check if we have write permission int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don't have permission so prompt the user ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE); }}private static final String TAG = "MyDownloadManager";private File downloadDir; // 文件保存路径private static MyDownloadManager instance; // 单例private String fileName;// 单线程任务队列public static Executor executor;private static final ThreadFactory sThreadFactory = new ThreadFactory() { private final AtomicInteger mCount = new AtomicInteger(1); public Thread newThread(Runnable r) { return new Thread(r, "MyDownloadManager #" + mCount.getAndIncrement()); }};private static final BlockingQueue sPoolWorkQueue = new LinkedBlockingQueue<>(128);public static final Executor THREAD_POOL_EXECUTOR = new ThreadPoolExecutor(1, 1, 1, TimeUnit.SECONDS, sPoolWorkQueue, sThreadFactory);public MyDownloadManager() { // 初始化下载路径 downloadDir = new File("/sdcard/"); if (!downloadDir.exists()) { downloadDir.mkdirs(); } executor = new SerialExecutor();}/** * 顺序执行下载任务 */private static class SerialExecutor implements Executor { final ArrayDeque mTasks = new ArrayDeque(); Runnable mActive; public synchronized void execute(final Runnable r) { mTasks.offer(new Runnable() { public void run() { try { r.run(); } finally { scheduleNext(); } } }); if (mActive == null) { scheduleNext(); } } protected synchronized void scheduleNext() { if ((mActive = mTasks.poll()) != null) { THREAD_POOL_EXECUTOR.execute(mActive); } }}/** * 获取单例对象 * * @return */public static MyDownloadManager getInstance() { if (instance == null) { instance = new MyDownloadManager(); } return instance;}/** * 添加下载任务 * * @param path */public void addDownloadTask(final String path) { Log.i(TAG, "进入run00"); executor.execute(new Runnable() { @Override public void run() { Log.i(TAG, "进入run"); download(path); } });}/** * 下载文件 * * @param path */private void download(String path) { String fileName = MainActivity.MD5(path); File savePath = new File(downloadDir, fileName); // 下载文件路径 //File finallyPath = new File(downloadDir, fileName + ".png"); // 下载完成后加入 if (savePath.exists()) { // 文件存在则已下载 Log.i(TAG, "file is existed"); return; } // 如果是Wifi则开始下载 if (savePath.exists() && savePath.delete()) { // 如果之前存在文件，证明没有下载完成，删掉重新创建 savePath = new File(downloadDir, fileName); Log.i(TAG, "download 111111"); } Log.i(TAG, "download start"); try { byte[] bs = new byte[1024]; int len; URL url = new URL(path); InputStream is = url.openStream(); OutputStream os = new FileOutputStream(savePath,true); Log.i(TAG, "download 22222"); while ((len = is.read(bs)) != -1) { os.write(bs, 0, len); } is.close(); os.close(); } catch (IOException e) { e.printStackTrace(); } //if (savePath.renameTo(finallyPath)) { // 下载完成后重命名为 // Log.i(TAG, "download end"); // }}/** * 添加删除任务 * * @param path */public void addDeleteTask(final String path) { executor.execute(new Runnable() { @Override public void run() { delete(path); } });}/** * 删除本地文件 * * @param path */private void delete(String path) { String fileName = MainActivity.MD5(path); File savePath = new File(downloadDir, fileName + ".png"); Log.i(TAG, savePath.getPath()); if (savePath.exists()) { if (savePath.delete()) { Log.i(TAG, "file is deleted"); } }}/** * 返回下载路径 * * @return */public File getDownloadDir() { return downloadDir;}public String getfileName(String path){ String f =MainActivity.MD5(path); return f;}} //
<?xml version="1.0" encoding="utf-8"?> //
<?xml version="1.0" encoding="utf-8"?> 代码中我有很多尝试的地方 注释的地方可以忽略 或者可以参考
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