java - 当我按下一个键时 onKeyUp 没有启动

Question

每次我按下一个键来启动 toast 时，我都会尝试，但似乎没有启动它，知道吗？

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = findViewById(R.id.txtKey);
        editText = findViewById(R.id.etxtKeyboard);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_P:
                Toast.makeText(this, "P pressed", Toast.LENGTH_SHORT).show();
                return true;
            default:
                return super.onKeyUp(keyCode, event);
        }
    }

Answer 1

正如 Android 文档中关于 Activity.onKeyUp() 方法的描述:

Called when a key was released and not handled by any of the views inside of the activity. So, for example, key presses while the cursor is inside a TextView will not trigger the event (unless it is a navigation to another object) because TextView handles its own key presses.

因此，当焦点位于 findViewById(R.id.etxtKeyboard); 编辑 TextView 时，您似乎正在 try catch onKeyUp() 事件。

您可以尝试在Activity.onCreate()中添加这样的代码:

editText.setOnKeyListener(
        new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                switch (keyCode) {
                    case KeyEvent.KEYCODE_P:
                        Toast.makeText(MyActivity.this, "P pressed", Toast.LENGTH_SHORT).show();
                        return true;
                    default:
                        return false;
                }
            }
        }
);