java - 自定义 View 调用了 setOnTouchListener 但没有覆盖 performClick(类扩展 Activity NOT View)

Question

我创建了一个实现了一些 OpenCV 的 Android Activity 。它的作用是简单地创建一个自定义相机 View ，当触摸屏幕时，照片将被保存。

我唯一的问题是 BaseLoaderCallback 中的代码 mOpenCvCameraView.setOnTouchListener(MainActivity.this); 包含警告。

mOpenCvCameraView.setOnTouchListener(MainActivity.this); 警告

Custom view com/example/zcameratestv2/Version2CameraView has setOnTouchListener called on it but does not override performClick

与其他问题不同，我的类(class)扩展了一个 Activity 而不是 View，所以当我尝试重写函数时 private boolean performClick() { ...super.performClick(); } 无法识别。这是我的类(class)

package com.example.zcameratestv2;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.OpenCVLoader;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.core.Mat;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.SurfaceView;
import android.view.View;
import android.view.WindowManager;
import android.view.View.OnTouchListener;
import android.widget.Toast;

public class MainActivity extends Activity implements CvCameraViewListener, OnTouchListener {

private Version2CameraView mOpenCvCameraView;
private static final String TAG = "Version 2::Activity";

private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
    @Override
    public void onManagerConnected(int status) {
        switch (status) {
            case LoaderCallbackInterface.SUCCESS:
            {
                Log.i(TAG, "OpenCV loaded successfully");
                mOpenCvCameraView.enableView();
                mOpenCvCameraView.setOnTouchListener(MainActivity.this);
            } break;
            default:
            {
                super.onManagerConnected(status);
            } break;
        }
    }
};

public MainActivity() {
    Log.i(TAG, "Version 2 Class instantiated");
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    setContentView(R.layout.activity_main);

    mOpenCvCameraView = (Version2CameraView) findViewById(R.id.java_surface_view);

    mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);

    mOpenCvCameraView.setCvCameraViewListener(this);

}

public void onPause()
{
    super.onPause();
    if (mOpenCvCameraView != null)
        mOpenCvCameraView.disableView();
}

@Override
public void onResume()
{
    super.onResume();
    OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
}

public void onDestroy() {
    super.onDestroy();
    if (mOpenCvCameraView != null)
        mOpenCvCameraView.disableView();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onCameraViewStarted(int width, int height) {
    // TODO Auto-generated method stub

}

@Override
public void onCameraViewStopped() {
    // TODO Auto-generated method stub

}

@Override
public Mat onCameraFrame(Mat inputFrame) {
    // TODO Auto-generated method stub
    return null;
}

@SuppressLint("SimpleDateFormat")
@Override
public boolean onTouch(View v, MotionEvent event) {
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
        //some code....
        break;
    case MotionEvent.ACTION_UP:
        Log.i(TAG,"onTouch event");
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss");
        String currentDateandTime = sdf.format(new Date());
        String fileName = Environment.getExternalStorageDirectory().getPath() +
                               "/sample_picture_" + currentDateandTime + ".jpg";
        mOpenCvCameraView.takePicture(fileName);
        Toast.makeText(this, fileName + " saved", Toast.LENGTH_SHORT).show();
        v.performClick();
        break;
    default:
        break;
    }
    return true;
 }


}

以前 public boolean onTouch(View v, MotionEvent event) 事件有一个类似于 OnTouchListener 的警告，它显示我应该使用 performClick();方法，但我无法覆盖它，因为我扩展到 Activity 而不是 View。我发现应用 v.PerformClick(); 可以解决这个问题。

这个其他类处理相机进程

package com.example.zcameratestv2;

import java.io.FileOutputStream;

import org.opencv.android.JavaCameraView;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.util.AttributeSet;
import android.util.Log;

public class Version2CameraView extends JavaCameraView implements PictureCallback {

private static final String TAG = "Version2::CameraView";
private String mPictureFileName;

public Version2CameraView(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public void takePicture(final String fileName) {
    Log.i(TAG, "Taking picture");
    this.mPictureFileName = fileName;
    // Postview and jpeg are sent in the same buffers if the queue is not empty when performing a capture.
    // Clear up buffers to avoid mCamera.takePicture to be stuck because of a memory issue
    mCamera.setPreviewCallback(null);

    // PictureCallback is implemented by the current class
    mCamera.takePicture(null, null, this);
}

@Override
public void onPictureTaken(byte[] data, Camera camera) {
    Log.i(TAG, "Saving a bitmap to file");
    // The camera preview was automatically stopped. Start it again.
    mCamera.startPreview();
    mCamera.setPreviewCallback(this);

    // Write the image in a file (in jpeg format)
    try {
        FileOutputStream fos = new FileOutputStream(mPictureFileName);

        fos.write(data);
        fos.close();

    } catch (java.io.IOException e) {
        Log.e("PictureDemo", "Exception in photoCallback", e);
    }

}
}

我已在 list 文件中包含所需的权限，例如 CAMERA 和 WRITE_EXTERNAL_STORAGE

有人可以确定问题所在吗？需要你的帮助。提前致谢!

Answer 1

onTouch() 方法从未标记为“已处理”的底层 View 中获取每个触摸事件。如果您的 Version2CameraView 不处理触摸事件，它们将在 Activity 中处理，并且您的 Version2CameraView 将作为 View v 参数传递。

不幸的是，您的 JavaCameraView 没有覆盖 performClick()，但您正在尝试在此 View 上调用它。解决方案？将此方法添加到您的 Version2CameraView 类:

@Override
public boolean performClick() {
    // do what you want
    return true;
}