今天完成一个画画板。
首先来个布局:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <ImageView android:id="@+id/iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/hello_world" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_alignParentBottom="true" > <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="红色" android:onClick="red" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="绿色" android:onClick="green" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="刷子" android:onClick="brush" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="保存" android:onClick="save" /> </LinearLayout> </RelativeLayout>
可见,要分红绿色,而且还要保存最后画的图片。
看一下主活动代码:
package com.itydl.paintban; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import android.net.Uri; import android.os.Bundle; import android.os.Environment; import android.app.Activity; import android.content.Intent; import android.graphics.Bitmap; import android.graphics.Bitmap.CompressFormat; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.view.Menu; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.widget.ImageView; public class MainActivity extends Activity { private ImageView iv; int startX; int startY; private Canvas canvas; private Paint paint; private Bitmap bmCopy; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //加载画画板的背景图 Bitmap bmSrc = BitmapFactory.decodeResource(getResources(), R.drawable.bg); bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(), bmSrc.getConfig()); paint = new Paint(); canvas = new Canvas(bmCopy); //绘制 canvas.drawBitmap(bmSrc, new Matrix(), paint); iv = (ImageView) findViewById(R.id.iv); iv.setImageBitmap(bmCopy); //设置触摸侦听 iv.setOnTouchListener(new OnTouchListener() { //触摸屏幕时,触摸事件产生时,此方法调用 @Override public boolean onTouch(View v, MotionEvent event) { int action = event.getAction(); switch (action) { //用户手指摸到屏幕 case MotionEvent.ACTION_DOWN: startX = (int) event.getX(); startY = (int) event.getY(); break; //用户手指正在滑动 case MotionEvent.ACTION_MOVE: int x = (int) event.getX(); int y = (int) event.getY(); canvas.drawLine(startX, startY, x, y, paint); //每次绘制完毕之后,本次绘制的结束坐标变成下一次绘制的初始坐标 startX = x; startY = y; iv.setImageBitmap(bmCopy); break; //用户手指离开屏幕 case MotionEvent.ACTION_UP: break; } //true:告诉系统,这个触摸事件由我来处理 //false:告诉系统,这个触摸事件我不处理,这时系统会把触摸事件传递给imageview的父节点 return true; } }); } public void red(View v){ paint.setColor(Color.RED); } public void green(View v){ paint.setColor(Color.GREEN); } public void brush(View v){ paint.setStrokeWidth(7); } public void save(View v){ File file = new File("sdcard/dazuo.png"); FileOutputStream fos = null; try { fos = new FileOutputStream(file); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } bmCopy.compress(CompressFormat.PNG, 100, fos); //发送sd卡就绪广播 Intent intent = new Intent(); intent.setAction(Intent.ACTION_MEDIA_MOUNTED); intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory())); sendBroadcast(intent); } }
运行看一下结果:
画了个绿帽子,哈哈。欢迎关注本博客点击打开链接 http://blog.csdn.net/qq_32059827,每天花上5分钟,阅读一篇有趣的安卓小文哦。