Question

我制作了一个非常简单的应用程序，我可以通过菜单中的按钮打开摄像机和照相机。以下是此应用的代码：

private static final int VIDEO_REQUEST_CODE=1;
private static final int IMAGE_REQUEST_CODE=2;

public void startRecord(){
    Intent videoIntent= new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
    File dir=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
    Uri fileUri=Uri.fromFile(new File(dir,"myVideo1.mp4"));
    videoIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
    videoIntent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
    startActivityForResult(videoIntent,VIDEO_REQUEST_CODE);
}

public void capturePhoto(){
    Intent imageIntent= new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    File dir=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
    Uri fileUri=Uri.fromFile(new File(dir,"myImage1.jpg"));
    imageIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
    startActivityForResult(imageIntent,IMAGE_REQUEST_CODE);

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()){
    case R.id.action_capture:
        capturePhoto();
    case R.id.action_record:
        startRecord();
        return true;
    }
    return false;
}

public void onActivityResult(int requestCode, int resultCode, Intent data){
    if(requestCode==VIDEO_REQUEST_CODE){
        if(resultCode==RESULT_OK){
            Toast.makeText(this,"Video saved to: "+data.getData(),Toast.LENGTH_LONG).show();
        }else if(resultCode==RESULT_CANCELED){
            Toast.makeText(this,"Record canceled",Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(this,"Record failed",Toast.LENGTH_LONG).show();
        }
    }else if(requestCode==IMAGE_REQUEST_CODE){
        if(resultCode==RESULT_OK){
            Toast.makeText(this,"Image saved to: "+data.getData(),Toast.LENGTH_LONG).show();
        }else if(resultCode==RESULT_CANCELED){
            Toast.makeText(this,"Image capture canceled",Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(this,"Image capture failed",Toast.LENGTH_LONG).show();
        }
    }
}

现在视频效果很好，但是当我尝试打开相机拍摄图像时，它也会自动打开视频摄像机。当我按＆＃34;返回＆＃34;之后图像相机打开，但是当我想拍照时，应用程序因运行时错误而关闭。它说failure delivering results to activity... ...attempt to invoke Uri on null object。我无法找到我的Uri的错误，所以任何人都可以解释我做错了什么？

Answer 1

那么有人可以解释我做错了什么吗？

您的switch写错了：

switch(item.getItemId()){
    case R.id.action_capture:
        capturePhoto();
    case R.id.action_record:
        startRecord();
        return true;
    }

选择R.id.action_capture后，您会同时拨打capturePhoto() 和 startRecord()，因为case R.id.action_capture部分并未以{{1}结尾}或break。

另请注意，return应该为data.getData()返回null。您正在设置ACTION_IMAGE_CAPTURE;看那里的照片。

图像意图打开摄像机并为Uri提供运行时异常

1 个答案: