Bitmap相关2：Bitmap.createBitmap()使用

 Bitmap 创建

[代码 步骤]

1. 创建Bitmaop 且指向icon.png

Bitmap ori = BitmapFactory.decodeResource(this.getResources(), R.drawable.icon);

2. 创建布局文件 有2个ImageView 一个供原图显示 一个供切割后显示

android:orientation="vertical"
android:layout_
android:layout_
android:id="@+id/layout"
>
android:layout_
android:layout_
android:id="@+id/image1"
android:layout_gravity="center_horizontal"
/>
android:layout_
android:layout_
android:id="@+id/image2"
android:layout_gravity="center"
/>

3. 初始化变量

lLauout = (LinearLayout)findViewById(R.id.layout);

iv1 = (ImageView)findViewById(R.id.image1);
iv2 = (ImageView)findViewById(R.id.image2);

4. 得到原图的宽度与高度 供后面使用

width = ori.getWidth();
height = ori.getHeight();

5.  定义变量 标志切割位置 并初始化之

int startX,startY,lengthX,lengthY;

startX = 0;
startY = 0;
lengthX = width;
lengthY = height;

 6. 如何选取图片位置

public boolean onKeyDown(int keyCode, KeyEvent msg){

switch(keyCode){
case KeyEvent.KEYCODE_DPAD_LEFT:
updateLeft();
break;

case KeyEvent.KEYCODE_DPAD_RIGHT:
updateRight();
break;
case KeyEvent.KEYCODE_DPAD_UP:
updateUp();
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
updateDown();
break;
case KeyEvent.KEYCODE_DPAD_CENTER:
showResult();
break;
}

return false;
}

7.  还需要判断移动是否合理

以下几种情况不合理：
1. 当图形左边 比 图形最大宽度 还大
2. 当图形上边 比 图形最大高度 还大
3. 图形宽度 或 高度 小于 0

public boolean isUpdateOK(){
if((startX > lengthX)||(startY > lengthY)||(lengthX > 0)||(lengthY > 0)){
return false;
}
else {
return true;
}
}

8. 具体移动方法：

public void updateLeft(){
startX += step;
lengthX = width-startX;
lengthY = height-startY;

if(isUpdateOK()){
target1.recycle();

target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);

iv2.setImageBitmap(target1);

setContentView(lLauout);
}
}
public void updateUp(){
startY += step;
lengthX = width-startX;
lengthY = height-startY;

if(isUpdateOK()){
target1.recycle();

target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);

iv2.setImageBitmap(target1);

setContentView(lLauout);
}
}
public void updateRight(){
lengthX -= step;

if(isUpdateOK()){
target1.recycle();

target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);

iv2.setImageBitmap(target1);

setContentView(lLauout);
}
}
public void updateDown(){
lengthY -= step;

if(isUpdateOK()){
target1.recycle();

target1 = Bitmap.createBitmap(ori,startX, startY, lengthX, lengthY);

iv2.setImageBitmap(target1);

setContentView(lLauout);
}
}
public void showResult(){
AlertDialog.Builder ab = new AlertDialog.Builder(this);
AlertDialog aDialog;

ab.setMessage("startX:"+startX+"\n"+"startY:"+startY+"\n"+"lengthX:"+lengthX+"\n"+"lengthY:"+lengthY).setTitle("show result").show();;
aDialog = ab.create();
aDialog.show();

}

9. emulator 运行情况： 

Bitmap 相关2：Bitmap.createBitmap() 使用