如何使用音量按钮放大/缩小textview中的文本

Question

如何覆盖和使用音量按钮缩放布局中的IN / OUT文本，类似于编写/阅读短信时的内容？

Answer 1

请检查此解决方案。

public class MainActivity extends AppCompatActivity {
    TextView txt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        txt = (TextView) findViewById(R.id.OpenClose);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) {
            float x = txt.getScaleX();
            float y = txt.getScaleY();

            txt.setScaleX(x - 1);
            txt.setScaleY(y - 1);
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_VOLUME_UP) {
            float x = txt.getScaleX();
            float y = txt.getScaleY();

            txt.setScaleX(x + 1);
            txt.setScaleY(y + 1);
            return true;
        } else {
            return super.onKeyDown(keyCode, event);
        }
    }
}