android - 以编程方式延迟添加视图

Question

我正在尝试在每个之间添加 4 X ImageView1 秒，我的代码是：delay

    final LinearLayout ll = (LinearLayout) findViewById(R.id.container);
    for (int j=0;j<4;j++){
        final ImageView newIMG = new ImageView(this);
        newIMG.setLayoutParams(
                        new LayoutParams(LayoutParams.WRAP_CONTENT, 
                                         LayoutParams.MATCH_PARENT, 
                                         1.0f));
        newIMG.setImageResource(R.drawable.new_image);
        Handler handler = new Handler(); 
        handler.postDelayed(new Runnable() { 
             public void run() { 
                    ll.addView(newIMG);
             } 
        }, 1000); 
    }

但我得到的是 - 它等待一秒钟然后一次display全部ImageViews......（我希望他们一个接一个地展示）

Answer 1

尝试 ：

final LinearLayout ll = (LinearLayout) findViewById(R.id.container);
for (int j=0;j<4;j++){
    final ImageView newIMG = new ImageView(this);
    newIMG.setLayoutParams(
                    new LayoutParams(LayoutParams.WRAP_CONTENT, 
                                     LayoutParams.MATCH_PARENT, 
                                     1.0f));
    newIMG.setImageResource(R.drawable.new_image);
    Handler handler = new Handler(); 
    handler.postDelayed(new Runnable() { 
         public void run() { 
                ll.addView(newIMG);
         } 
    }, j*1000 + 1000); 
}

Answer 2

尝试这个：

 int id = 999;
     final LinearLayout ll = (LinearLayout) findViewById(R.id.LinearLayout1);
        for (int j=0;j<4;j++){
            final ImageView newIMG = new ImageView(this);

            newIMG.setImageResource(R.drawable.ic_launcher);
            newIMG.setId(id);
            RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
            params.setMargins(0, 10, 0, 0);
            params.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);

            if(j > 0) {
                params.addRule(RelativeLayout.BELOW, id - j);
            }

            Handler handler = new Handler(); 
            handler.postDelayed(new Runnable() { 
                 public void run() { 
                        ll.addView(newIMG);
                 } 
            }, (j+1)*1000);
            newIMG.setLayoutParams(params);
            id++;
        }

Answer 3

如果您不想让大量线程同时运行且延迟交错，您可以执行以下操作：

public class MainActivity extends Activity {

    private int viewsAddedCount = 0;

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

        Button b = (Button)findViewById(R.id.button1);
        b.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                v.setEnabled(false);
                Thread thread = new delayedViewAdditionThread();
                thread.start();
            }           
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    public class delayedViewAdditionThread extends Thread
    {
        private android.os.Handler handler = new android.os.Handler()
        {
            @Override             
            public void handleMessage(android.os.Message msg) 
            {                 
                switch(msg.what)
                {
                    case 0 :
                        addTextView();
                        break;
                    case 1 :
                        Button b = (Button)findViewById(R.id.button1);
                        b.setEnabled(true);
                        break;
                    default :
                        break;
                }
            }
        };
        @Override
        public void run()
        {   
            for(int i = 0; i < 4; i++)
            {
                try 
                {
                    Thread.sleep(1000);
                } 
                catch (InterruptedException e) 
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }           
                handler.sendEmptyMessage(0);                
            }
            handler.sendEmptyMessage(1);
        }

        private void addTextView()
        {
            TextView tv = new TextView(MainActivity.this);
            tv.setText("TextView No. " + String.valueOf(viewsAddedCount + 1));
            tv.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));

            LinearLayout ll = (LinearLayout)findViewById(R.id.expandingLayout);
            ll.addView(tv);

            viewsAddedCount++;
        }
    }

}