我正在使用canvas的应用程序。我正在使用自定义imageview。但是当我尝试运行应用程序时，我收到一个错误。我写的代码如下
private static MyView myimageView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
Uri selectedImage = data.getData();
String[] filePathColumn = { MediaStore.Images.Media.DATA };
myimageView = (MyView) findViewById(R.id.myView);
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
myimageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
Intent i = getIntent();
loc = i.getFloatArrayExtra("Location");
myimageView.buildDrawingCache();
bmp1 = Bitmap.createBitmap(myimageView.getDrawingCache());
bmp2 = Bitmap.createBitmap(myimageView.getDrawingCache());
}
}
public static class MyView extends ImageView implements OnTouchListener{ // or some other View-based class
public MyView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
MyView(Context context, AttributeSet attrs) {
super(context, attrs);
}
MyView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
boolean drawRectangle = false;
PointF beginCoordinate;
PointF endCoordinate;
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
int count=1;
if(event.getAction() ==MotionEvent.ACTION_DOWN) {
if (count==1){
x1 = event.getX();
y1 = event.getY();
System.out.println(count+"count of value a;skd");
Log.i(TAG, "coordinate x1 : "+String.valueOf(x1)+" y1 : "+String.valueOf(y1));
}
}
else if(event.getAction() ==MotionEvent.ACTION_MOVE){
invalidate();
// imageView.setImageBitmap(bmp2);
x2 = event.getX();
y2 = event.getY();
posX=(float)(x1+x2)/2;
posY=(float)(y1+y2)/2;
radius=(float) Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2))/2;
// onDraw();
}
if(event.getAction() ==MotionEvent.ACTION_UP)
{
invalidate();
// onDraw();
//bmp2=bmp;
if(action==2)
{
}
}
return true;
}
public void onDraw(){
bmp = Bitmap.createBitmap(myimageView.getWidth(), myimageView.getHeight(), Config.ARGB_8888);
c = new Canvas(bmp);
myimageView.draw(c);
Paint pnt = new Paint();
pnt.setColor(Color.BLUE);
pnt.setStyle(Paint.Style.STROKE);
pnt.setStrokeWidth(3);
if(action==1)
{
c.drawCircle(posX,posY, radius, pnt);
pnt.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
myimageView.setImageBitmap(bmp);
i = 1;
}else{
float h=(float) 30.0;
float phi = (float) Math.atan2(y2 - y1, x2 - x1);
float angle1 = (float) (phi - Math.PI / 6);
float angle2 = (float) (phi + Math.PI / 6);
float x3 = (float) (x2 - h * Math.cos(angle1));
float x4 = (float) (x2 - h * Math.cos(angle2));
float y3 = (float) (y2 - h * Math.sin(angle1));
float y4 = (float) (y2 - h * Math.sin(angle2));
c.drawLine(x1, y1,x2,y2 ,pnt);
c.drawLine(x2, y2,x3,y3 ,pnt);
c.drawLine(x2, y2,x4,y4 ,pnt);
myimageView.setImageBitmap(bmp);
i=1;
}
}
}
}
在我的xml文件中，我得到的错误是：
<ImageView class= "com.infy.DrawActivity$MyView" android:id="@+id/myView" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="1.01" android:src="@drawable/ic_launcher" />
和log cat是：
07-23 10:47:13.098: E/AndroidRuntime(815): FATAL EXCEPTION: main
07-23 10:47:13.098: E/AndroidRuntime(815): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { dat=content://media/external/images/media/29 }} to activity {com.infy/com.infy.DrawActivity}: java.lang.ClassCastException: android.widget.ImageView cannot be cast to com.infy.DrawActivity$MyView
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread.deliverResults(ActivityThread.java:2980)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3023)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread.access$1100(ActivityThread.java:123)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1177)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.os.Handler.dispatchMessage(Handler.java:99)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.os.Looper.loop(Looper.java:137)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread.main(ActivityThread.java:4424)
07-23 10:47:13.098: E/AndroidRuntime(815): at java.lang.reflect.Method.invokeNative(Native Method)
07-23 10:47:13.098: E/AndroidRuntime(815): at java.lang.reflect.Method.invoke(Method.java:511)
07-23 10:47:13.098: E/AndroidRuntime(815): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-23 10:47:13.098: E/AndroidRuntime(815): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-23 10:47:13.098: E/AndroidRuntime(815): at dalvik.system.NativeStart.main(Native Method)
07-23 10:47:13.098: E/AndroidRuntime(815): Caused by: java.lang.ClassCastException: android.widget.ImageView cannot be cast to com.infy.DrawActivity$MyView
07-23 10:47:13.098: E/AndroidRuntime(815): at com.infy.DrawActivity.onActivityResult(DrawActivity.java:153)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.Activity.dispatchActivityResult(Activity.java:4649)
07-23 10:47:13.098: E/AndroidRuntime(815): at android.app.ActivityThread.deliverResults(ActivityThread.java:2976)
07-23 10:47:13.098: E/AndroidRuntime(815): ... 11 more
答案 0 :(得分：2)
它是DrawActivity的内部类，因此您需要在XML中引用它，如下所示：
<view class="com.infy.DrawActivity$myView"
android:id="@+id/myView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1.01"
android:src="@drawable/ic_launcher" />
见这里：Error referencing an inner class View in layout/main.xml
或者，将它移到它自己的班级。
答案 1 :(得分：1)
将您的类定义为public static并添加所有必需的View构造函数
public static class myView extends ImageView {
myView(Context context) {
super(context);
}
myView(Context context, AttributeSet attrs) {
super(context, attrs)
}
myView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
并像这样引用它
<view class="com.infy.DrawActivity$myView"
android:id="@+id/myView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1.01"
android:src="@drawable/ic_launcher" />
提示：根据Java约定，类名应以大写字母开头。
答案 2 :(得分：1)
尝试添加
myView(Context context, AttributeSet attrs) and myView(Context context, AttributeSet attrs, int defStyle)
在自定义ImageView中。