Question

我正在尝试根据微调器选择在imageview中更改图像，在stackoverflow和internet上查找类似的东西，但没有任何效果！为什么？任何帮助赞赏！这是我的.java来源：

公共类ChordsActivity扩展Activity实现OnItemSelectedListener { 旋转器旋转器;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_chords);
    spinner = (Spinner) findViewById(R.id.SpinnerAkordi);
    spinner.setOnItemSelectedListener(this);

    ImageView chord_img=(ImageView) findViewById(R.id.image);
    chord_img.setImageResource(R.drawable.c_dur);
}



@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
    int position = spinner.getSelectedItemPosition ();
    ImageView chord_img= new ImageView(this); //delete this and it will work
    switch (position){
    case 0:
        new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("C").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.c_dur);
        break;
    case 1:
        new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("D").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.e_dur);
        break;
    case 2:
    new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("E").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.e_dur);
        break;
    }
}

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub

}

}

.xml的imageview部分：

答案：删除：ImageView chord_img = new ImageView（this）; 因为我已经有了一个imageview，我用这条线创建了一个看不见的新imageview。

Answer 1

如果将局部变量chord_img提升为字段，则可能有所帮助。即：

private ImageView chord_img;

@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
    int position = spinner.getSelectedItemPosition ();
    chord_img = new ImageView(this);
    switch (position){
    case 0:
        new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("C").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.c_dur);
        break;
    case 1:
        new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("D").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.e_dur);
        break;
    case 2:
    new AlertDialog.Builder(this).setTitle("Odabrali ste akord:").setMessage("E").setNeutralButton("Close", null).show();
        chord_img.setImageResource(R.drawable.e_dur);
        break;
    }
}

如何根据微调器选择更改imageview图像？

1 个答案: