java - 从图库中选择图像在 android 中不起作用

Question

我正在尝试从图库中选择一张图片以在 ImageView 中显示，选择有效但图像没有出现在 ImageView 中，它仍然是空白的。

代码:

public class MainActivity extends AppCompatActivity {

    private static final int SELECTED_PICTURE=1;
    ImageView iv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        iv=(ImageView)findViewById(R.id.imageView1);

        //FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        //fab.setOnClickListener(new View.OnClickListener() {
            //@Override
            //public void onClick(View view) {
                //Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        //.setAction("Action", null).show();
            //}
        }//);
    public void btnClick(View v){
        Intent i=new Intent(Intent.ACTION_PICK,android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(i, SELECTED_PICTURE);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
            case SELECTED_PICTURE:
                if(resultCode==RESULT_OK){
                    Uri uri=data.getData();
                    String[]projection={MediaStore.Images.Media.DATA};

                    Cursor cursor=getContentResolver().query(uri, projection, null, null, null);
                    cursor.moveToFirst();

                    int columnIndex=cursor.getColumnIndex(projection[0]);
                    String filePath=cursor.getString(columnIndex);
                    cursor.close();

                    Bitmap yourSelectedImage=BitmapFactory.decodeFile(filePath);
                    Drawable d=new BitmapDrawable(yourSelectedImage);

                    iv.setBackground(d);

                }
                break;

            default:
                break;
        }
    }
}

我做错了什么？

Answer 1

试试下面的代码；

iv.setImageBitmap(yourSelectedImage);

而不是下面的代码；

 Drawable d=new BitmapDrawable(yourSelectedImage);
 iv.setBackground(d);