Question

我想打印如下：

for(int i=0;i<should be infinite;i++)
{
    Data is Loading.
    sleep(100);
    Data is Loading..
    sleep(100);
    Data is Loading... 
    sleep(100);
}

以下是无效的代码

package com.queen.a01_simple_request;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
TextView textView;
Button button;

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

    textView = (TextView) findViewById(R.id.textView);
    button = (Button) findViewById(R.id.button);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for (; ; ) {
                try {
                    textView.setText("Downloading The File");
                    Thread.sleep(1000);
                    textView.setText("Downloading The File.");
                    Thread.sleep(1000);
                    textView.setText("Downloading The File..");
                    Thread.sleep(1000);
                    textView.setText("Downloading The File...");
                    Thread.sleep(1000);

                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    });
}

}

现在，这应该循环无限。点应该永远一个接一个地改变。我不想像i <1000那样设置值。我想实现这一点。

Answer 1

basic for statement的前3个“部分”是可选的：

for ( [ForInit] ; [Expression] ; [ForUpdate] ) Statement

所以，虽然看起来很奇怪，但这是一个有效的for循环（永远不会做任何事情）：

for (;;);

在您的情况下，只需省略Expression：

for (int i = 0; ; i++) { ... }

Answer 2

    for(;;){
    {
    try{
     Data is Loading.
     Thread.sleep(100);
     Data is Loading..
     Thread.sleep(100);
     Data is Loading... 
     Thread.sleep(100);
    }catch(Exception ignored){}
    }

编辑： 如果你在主线程（UI线程）上执行此操作，它将冻结应用程序，你必须在后台启动循环，如下所示：

new Thread(new Runnable(){
   @Override
   public void run(){
       for(;;){
            try{
             Data is Loading.
             Thread.sleep(100);
             Data is Loading..
             Thread.sleep(100);
             Data is Loading... 
             Thread.sleep(100);
            }catch(Exception ignored){}
        }
    }
}

Answer 3

试试这个：

while(true){
   code...
}

使用循环重复语句无限次？

3 个答案: