今天学习了一些安卓开发中的自定义布局,编写了简单一个实例,“跟随手指移动的鸟”,需要两张图片,背景图片和鸟的图片,鸟的图片可以在屏幕中跟随手指的移动而移动。
1.将两张图片导入到mipmap中;
2.首先设置背景,用到了background方法,并设置其id;
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
android:paddingBottom="16dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="16dp"
android:background="@mipmap/background"
android:id="@+id/aaa"
tools:context=".MainActivity"> </FrameLayout>
3.编写java代码继承View,设置鸟的图片的默认显示位置,bitmapx和bitmapy,分别为x坐标和y坐标,然后重写onDraw方法
package com.example.myview;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;
public class BirdView extends View{
public float bitmapx;
public float bitmapy;
public BirdView(Context context) {
super(context);
bitmapx=290;
bitmapy=130;
} @Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint=new Paint();
Bitmap bitmap=BitmapFactory.decodeResource(this.getResources(),R.mipmap.bird1);
canvas.drawBitmap(bitmap,bitmapx,bitmapy,paint);
if (bitmap.isRecycled()){
bitmap.recycle();
}
}
}
3.编写主方法,并测试结果。
package com.example.myview; import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout; public class MainActivity extends AppCompatActivity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FrameLayout frameLayout=(FrameLayout) findViewById(R.id.aaa);
final BirdView birdView=new BirdView(this);
birdView.setOnTouchListener(new View.OnTouchListener() { //触摸动作监听
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
birdView.bitmapx= motionEvent.getX();
birdView.bitmapy=motionEvent.getY();
birdView.invalidate();
return true;
}
});
frameLayout.addView(birdView);
}
}