Question

我试图在调用特定方法时运行一个线程。像这样：

private void changeSize(final Bitmap image) {
  Thread task = new Thread(new Runnable() {
     @Override
     public void run() {
            byte[] image;
            int width = image.getWidth();
            int height = image.getHeight();
            int newHeight = 0, newWidth = 0;
            if (width > 350 || height > 350) {
                if (width > height) { 
                    newHeight = 350;
                    newWidth = (newHeight * width) / height;
                } else { 
                    nyBredden = 350;
                    newHeight = (newWidth * height) / width;
                }
            } else {
                Toast.makeText(context, "test", Toast.LENGTH_LONG).show();
                }
            Bitmap sizeChanged = Bitmap.createScaledBitmap(image, newWidth, newHeight, true);
            if (sizeChanged != null) {
                Toast.makeText(context, "test", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(context, "test", Toast.LENGTH_SHORT).show();
            }
            ByteArrayOutputStream stream = new ByteArrayOutputStream();

            if (sizeChanged.getHeight() >= 350 || sizeChanged.getWidth() >= 350) {
                sizeChanged.compress(Bitmap.CompressFormat.JPEG, 90, stream);
            } else {
                sizeChanged.compress(Bitmap.CompressFormat.JPEG, 100, stream);
            }

            image = stream.toByteArray();
            if (image != null) {
                myImage(image); //method
                File path = context.getExternalFilesDir(Environment.DIRECTORY_PICTURES);
                String namechanged = edMyType.getText().toString() + "_scalledDown" + ".jpg";

                File file = new File(path, namechanged);
                FileOutputStream fos = null;
                try {
                    fos = new FileOutputStream(file);
                    fos.write(image);
                    fos.flush();
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    try {
                        if (fos != null) {
                            fos.close();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } else {
                Toast.makeText(context, "test", Toast.LENGTH_SHORT).show();
            }
        }
     }
  });
  task.start(); 
}

当我调用此方法时，我的应用程序崩溃了。我试图调试，但我不理解变量，例如：

task: "Thread[Thread-149,5,main]"
hasBeenStarted = false

当我按下按钮拍照时，会调用该方法。请任何人知道我在哪里做错了或运行这样的线程是否正确？

Answer 1

您无法在后台线程中显示Toast。

移除吐司并使用例如用于调试目的的日志记录，或者通过使用例如将toast转移到主UI线程。 Activity runOnUiThread()或Handler。

Answer 2

希望这有帮助！

>>> A[[[1, 1],[3, 3]], [[1, 3], [1, 3]]] = 1

Answer 3

你应该使用Handler ......

private void changeSize(final Bitmap image) {
 Thread task = new Thread(new Runnable() {
     @Override
     public void run() {

     }
      private final Handler handler = new Handler() {
           //some code here..
      };
 });
 task.start(); 
}

Answer 4

Thread splashThread = new Thread() {
            public void run() {
                synchronized (this) {
                    try {
                        wait(2000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    startActivity(new Intent(getApplicationContext(),
                            MainActivity.class));
                    finish();
                }
            }
        };
        splashThread.start();

尝试使用我的代码。我希望这会对你有所帮助。

当我在Android中运行Runnable线程时，为什么我的应用程序崩溃？

4 个答案: