Question

我正在尝试使用不同的字符串每3秒更新一次TextView。我有一个处理程序和runnable设置，但是当我运行它时，它会自动显示最后一个setText。我已经尝试将ms更改为3000,6000等，并且在运行之前也尝试过removeCallbacks。任何帮助将不胜感激！

final Handler handler = new Handler();

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

    final Runnable r = new Runnable(){
        @Override
        public void run(){
            TextView text = (TextView)findViewById(R.id.textView4);
            text.setText("1");
            handler.postDelayed(this, 3000);
            text.setText("2");
            handler.postDelayed(this, 3000);
            text.setText("3");
            handler.postDelayed(this, 3000);
            text.setText("4");
            handler.postDelayed(this, 3000);
            text.setText("5");


        }
    };

    handler.postDelayed(r, 0);


}

Answer 1

像这样更改你的代码

private String[] messages = {"1", "2", "3", "4", "5"};
    final Handler handler = new Handler();
    private int nextIndex;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.workout);
        final TextView text = (TextView)findViewById(R.id.textView4);
        final Runnable r = new Runnable(){
            @Override
            public void run(){
                if (messages.length > nextIndex) {
                    text.setText(messages[nextIndex++]);
                    handler.postDelayed(this, 3000);
                }
            }
        };

        handler.postDelayed(r, 0);
    }

使用Handler更新TextVIew仅显示上次更改

1 个答案: