Question

我正在使用System.NanoTime来跟踪已用时间，但它不会在UI上更新。以下是我的代码：

然而，我正在使用onCreate()方法做所有事情，我采取的方法可能不够强大，但这就是我想要更多想法的地方。

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


    long startTime = System.nanoTime();
    // ... the code being measured ...
    long estimatedTime = (System.nanoTime() - startTime) / 1000000000;
    System.out.println(""+estimatedTime);
    while (estimatedTime <= 100){
        System.out.println(""+estimatedTime);

        if(estimatedTime == 1){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Preparing"); 

        }
        if(estimatedTime == 2){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Inatializing"); 

        }
        if(estimatedTime == 3){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Preparing to install"); 

        }
        if(estimatedTime == 4){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Installing"); 

        }
        if(estimatedTime == 5){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Installed"); 

        }
        if(estimatedTime == 6){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Unzipping packages..."); 

        }


        estimatedTime = (System.nanoTime() - startTime) / 1000000000;
    }

}

Answer 1

也许你可以试试：

tx.postInvalidate();

其中tx是您的TextView对象

这一行之后：

estimatedTime = (System.nanoTime() - startTime) / 1000000000;

但是你应该将所有这些代码放在Thread下面。例如：

new Thread(new Runnable() {

        @Override
        public void run() {
            //your code here
        }
    }).start();

更新：使用此更新主线程：

YourActivity.this.runOnUiThread(new Runnable() {
    @Override
    public void run() {
        //here set text into textView
    }
});

Answer 2

您无法在UI线程中执行此操作作为其阻止。您应该将其移动到AsyncTask。

Answer 3

使用另一个线程并调用runOnUiThread方法并传递该线程的对象。如下所示

Thread th=new Thread(new Runnable() {



        @Override
        public void run() {
            //put your code here
while (estimatedTime <= 100){
Thread.sleep(1000);
            System.out.println(""+estimatedTime);

        if(estimatedTime == 1){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Preparing"); 

        }
        if(estimatedTime == 2){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Inatializing"); 

        }
        if(estimatedTime == 3){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Preparing to install"); 

        }
        if(estimatedTime == 4){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Installing"); 

        }
        if(estimatedTime == 5){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Installed"); 

        }
        if(estimatedTime == 6){
            TextView tx = (TextView)findViewById(R.id.textView);
            tx.setText("Unzipping packages..."); 

        }


        estimatedTime = (System.nanoTime() - startTime) / 1000000000;
        }
    });

runOnUiThread（TH）;

Answer 4

最好使用Handler延迟某项任务......

Handler handler = new Handler();
handler.postDelayed(new Runnable(){ 
    public void Run(){
        //Put your code here. Code will execute after 1000ms
    }
}, 1000);

经过一段时间后更新textView

4 个答案: