首先我们要理解什么是帧布局,真不剧中每一个组件都代表一个画面,默认以屏幕左上角作为(0,0)坐标,组件按定义的先后顺序一次逐屏显示,后面出现的会覆盖前面的画面。下面我们就用该布局实现霓虹灯的效果,如图:
布局文件中定义七个视图组件,最大的在最下面,先定义,最小的在最上面,最后定义
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:layout_gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/view1"
android:width="200px"
android:height="200px"
android:layout_gravity="center"
android:background="#ff0000"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/view2"
android:width="170px"
android:height="170px"
android:layout_gravity="center"
android:background="#bb0000"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/view3"
android:width="140px"
android:height="140px"
android:layout_gravity="center"
android:background="#990000"/>
<TextView
android:id="@+id/view4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="#770000"
android:height="110px"
android:width="110px" />
<TextView
android:id="@+id/view5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="#f0ff00"
android:height="50px"
android:width="50px" />
<TextView
android:id="@+id/view6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="#550000"
android:height="80px"
android:width="80px" />
<TextView
android:id="@+id/view7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:background="#330000"
android:height="50px"
android:width="50px" />
</FrameLayout>
在values目录下,new一个存放color的xml文件:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="color1">#330000</color>
<color name="color2">#550000</color>
<color name="color3">#770000</color>
<color name="color4">#990000</color>
<color name="color5">#bb0000</color>
<color name="color6">#dd0000</color>
<color name="color7">#ff0000</color>
</resources>
Activity中代码编写:
package cn.sword.activity;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.widget.TextView;
public class FrameLayoutTaskActivity extends Activity {
boolean flag = true;
private int currentColor = 0;
final int[] colors = new int[] { R.color.color7,R.color.color6,R.color.color5,R.color.color4, R.color.color3,
R.color.color2, R.color.color1, };
final int[] names = new int[] { R.id.view1, R.id.view2, R.id.view3,
R.id.view4, R.id.view5, R.id.view6, R.id.view7 };
TextView[] views = new TextView[7];
class MyHandler extends Handler {
public void handleMessage(Message msg) {
show();
sleep((long) 100);
}
void show() {
for (int i = 0; i < 7 - currentColor; i++) {
views[i].setBackgroundResource(colors[i + currentColor]);
}
for (int i = 6 - currentColor, j = 0; i < 7; i++, j++) {
views[i].setBackgroundResource(colors[j]);
}
currentColor++;
if(currentColor>=7){
currentColor=0;
}
}
public void sleep(Long delayMillis) {
if (flag){
this.sendMessageDelayed(this.obtainMessage(0), delayMillis);
}
}
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
for (int i = 0; i < 7; i++) {
views[i] = (TextView) findViewById(names[i]);
}
MyHandler handler = new MyHandler();
handler.sleep((long) 100);
}
}