Question

我尝试测试演示以上传录制的视频我收到这个错误：

ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference

我使用这个演示： uploading-camera-image-video-to-server-with-progress-bar

我可以录制视频但是当我点击“保存”转到其他活动以进行Uplading文件时，我收到上述错误

错误在于OnCreate：

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_upload);
    txtPercentage = (TextView) findViewById(R.id.txtPercentage);
    btnUpload = (Button) findViewById(R.id.btnUpload);
    progressBar = (ProgressBar) findViewById(R.id.progressBar);
    imgPreview = (ImageView) findViewById(R.id.imgPreview);
    vidPreview = (VideoView) findViewById(R.id.videoPreview);

    // Changing action bar background color
    getActionBar().setBackgroundDrawable(
            new ColorDrawable(Color.parseColor(getResources().getString(
                    R.color.action_bar))));

    // Receiving the data from previous activity
    Intent i = getIntent();

    // image or video path that is captured in previous activity
    filePath = i.getStringExtra("filePath");

    // boolean flag to identify the media type, image or video
    boolean isImage = i.getBooleanExtra("isImage", true);

    if (filePath != null) {
        // Displaying the image or video on the screen
        previewMedia(isImage);
    } else {
        Toast.makeText(getApplicationContext(),
                "Sorry, file path is missing!", Toast.LENGTH_LONG).show();
    }

    btnUpload.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // uploading the file to server
            new UploadFileToServer().execute();
        }
    });

}

Answer 1

我删除了这行颜色后修复了错误：

//getActionBar().setBackgroundDrawable(
        new ColorDrawable(Color.parseColor(getResources().getString(
                R.color.action_bar))));

对空引用引用的ActionBar.setBackgroundDrawable（android.graphics.drawable.Drawable）'

1 个答案: