1.自定义View
@SuppressLint("AppCompatCustomView")
public class Random extends TextView{
public Random(Context context) {
super(context);
init();
}
public Random(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
//设置点击事件
private void init(){
changeText();
setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
changeText();
}
});
}
int i = 0;
//随机改变数字和背景
private void changeText(){
setText(String.valueOf(getRandom()));
if(i % 2 == 0){
setBackgroundColor(Color.BLACK);
}else{
setBackgroundColor(Color.RED);
}
i++;
}
//获取随机数的方法
private int getRandom(){
return (int) (Math.random()*9000+1000);
}
}
2.Xml布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.example.random_num.Random
android:layout_width="200dp"
android:layout_height="100dp"
android:gravity="center"
android:layout_centerInParent="true"
android:background="#000"
android:textSize="40sp"
android:textColor="#fcc"
/>
</RelativeLayout>
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