AndroidStudio图片上涂鸦程序
Allison-L 人气:0一、内容:设计一个能在图片上涂鸦的程序
二、实现
1. 布局文件activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout 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" android:orientation="vertical"> <com.example.asus.test442.HandWrite android:layout_width="match_parent" android:layout_height="550dp" android:id="@+id/hw"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:text="clear" android:id="@+id/btn"/> </LinearLayout> </LinearLayout>
2. 主控文件MainActivity.java
package com.example.asus.test442; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; public class MainActivity extends AppCompatActivity { private HandWrite handWrite = null; Button clear = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); handWrite = (HandWrite)findViewById(R.id.hw); //关联view组件 clear = (Button)findViewById(R.id.btn); clear.setOnClickListener(new click()); } private class click implements View.OnClickListener { @Override public void onClick(View view) { handWrite.clear(); } } }
3. 记录在屏幕上滑动的轨迹,实现在图片上涂鸦的功能 HandWrite.java
package com.example.asus.test442; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; public class HandWrite extends View { Paint paint = null; //定义画笔 Bitmap origBit = null; //存放原始图像 Bitmap new_1Bit = null; //存放从原始图像复制的位图图像 Bitmap new_2Bit = null; //存放处理后的图像 float startX = 0,startY = 0; //画线的起点坐标 float clickX = 0, clickY = 0; //画线的终点坐标 boolean isMove = true; //设置是否画线的标记 boolean isClear = false; //设置是否清除涂鸦的标记 int color = Color.BLUE; //设置画笔的颜色 float strokeWidth = 2.0f; //设置画笔的宽度 public HandWrite(Context context, AttributeSet attrs) { super(context, attrs); // 从资源中获取原始图像 origBit = BitmapFactory.decodeResource(getResources(),R.drawable.p1).copy(Bitmap.Config.ARGB_8888,true); // 建立原始图像的位图 new_1Bit = Bitmap.createBitmap(origBit); } // 清除涂鸦 public void clear() { isClear = true; new_2Bit = Bitmap.createBitmap(origBit); invalidate(); } public void setSyle(float strokeWidth) { this.strokeWidth = strokeWidth; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.drawBitmap(HandWriting(new_1Bit),0,0,null); } private Bitmap HandWriting(Bitmap newBit) { //记录绘制图形 Canvas canvas = null; // 定义画布 if (isClear) { // 创建绘制新图形的画布 canvas = new Canvas(new_2Bit); } else { canvas = new Canvas(newBit); //创建绘制原图形的画布 } paint = new Paint(); paint.setStyle(Paint.Style.STROKE); paint.setAntiAlias(true); paint.setColor(color); paint.setStrokeWidth(strokeWidth); if (isMove){ canvas.drawLine(startX,startY,clickX,clickY,paint); // 在画布上画线条 } startX = clickX; startY = clickY; if (isClear){ return new_2Bit; // 返回新绘制的图像 } return newBit; // 若清屏,则返回原图像 } // 定义触摸屏事件 @Override public boolean onTouchEvent(MotionEvent event) { clickX = event.getX(); // 获取触摸坐标位置 clickY = event.getY(); if (event.getAction() == MotionEvent.ACTION_DOWN) { // 按下屏幕时无绘图 isMove = false; invalidate(); return true; } else if (event.getAction() == MotionEvent.ACTION_MOVE) { // 记录在屏幕上划动的轨迹 isMove = true; invalidate(); return true; } return super.onTouchEvent(event); } }
三、效果
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