Question

我是java的新手，制作了第一款游戏。所以，我需要我的按钮“FLASH”在设置背景资源后显示我的图片“on”，目前它跳过它，在代码结束时它变为“off”值，我已经尝试了几个我可以在网上找到的方法。

我试过了：

FLASH.invalidate;
----
ViewGroup vg = (ViewGroup) findViewById(R.id.parent);
vg.invalidate;
----
//setting FLASH as a togglebutton, with an xml file in drawable, which works when clicked
FLASH.setChecked(true);
----
FLASH.jumpDrawablesToCurrentState();
----
ViewGroup vg = (ViewGroup) findViewById(R.id.parent);
vg.jumpDrawablesToCurrentState();
----
FLASH.performClick;
----
//making giant loops and functions with if's or different calls to functions so it could refresh at the end of it

一切都无济于事

package net.myfreesites.httpmatthigast.test;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
//import android.view.ViewGroup;
import android.widget.Button;
public class MainActivity extends AppCompatActivity 
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void onStart()
    {
        super.onStart();
        game();
    }
    public void game()
    {
        final Button GO;
        GO = (Button) findViewById(R.id.Start);
        GO.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                Button FLASH;
                FLASH = (Button) findViewById(R.id.Flash);
                try
                {
                    FLASH.setBackgroundResource(R.drawable.on);
                    //Here I need something that forces the image "on" onto my FLASH-Button
                    Thread.sleep(500);
                    FLASH.setBackgroundResource(R.drawable.off);
                    Thread.sleep(500);
                }
                    catch (InterruptedException ignored)
                {
                }
            }
        });
    }
}

（这不是我游戏的代码，只是一个按钮，如果我点击GO-Button后可以让这一个闪光，我可以让我的游戏中的那些闪光（这是我的整个点）游戏））

提前感谢：）

Answer 1

使用ViewTreeObserver在父布局上的runtime.set treeobserver上刷新布局，并更改子视图中的任何内容。搜索View Tree Observer或查找信息here

final LinearLayout layout = (LinearLayout) findViewById(R.id.YOUR_VIEW_ID);
ViewTreeObserver vto = layout.getViewTreeObserver(); 
vto.addOnGlobalLayoutListener (new OnGlobalLayoutListener() { 
@Override 
public void onGlobalLayout() {
    // refresh or add drawable here with condition
    layout.getViewTreeObserver().removeOnGlobalLayoutListener(this); 


} 
});

如何在java / android中强制刷新布局为可绘制值

1 个答案: