【发布时间】：2013-03-06 16:10:33
【问题描述】：
我一直在尝试使我的应用程序能够滚动我的自定义视图（水平和垂直），以使用户能够绘制的不仅仅是初始屏幕大小。该应用程序将用于生成基本的房屋计划，例如用户绘制连接的矩形代表他们的家。
我正在使用我在活动中设置（作为内部类）的自定义视图。在广泛搜索并看到人们在滚动视图中遇到的问题之后，这是我所能得到的。这是我的 XML：
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<com.example.HomerProject1stDraft.DrawNewPlans.HomerView
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</com.example.HomerProject1stDraft.DrawNewPlans.HomerView>
</LinearLayout>
如您所见，我正在尝试添加 HomerView 类，该类位于 DrawNewPlans 类（活动）中。
这里是onCreate() 方法：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.drawnew);
}
这是我的自定义视图的代码（记住它包含在另一个类中）：
class HomerView extends View { // the custom View for drawing on
// set up Bitmap, canvas, path and paint
private Bitmap myBitmap; // the initial image we turn into our canvas
private Canvas myCanvas; // the canvas we are drawing on
private Rect myRect; // the mathematical path of the lines we draw
private Paint myBitmapPaint; // the paint we use to draw the bitmap
// get the width of the entire tablet screen
private int screenWidth = getContext().getResources()
.getDisplayMetrics().widthPixels;
// get the height of the entire tablet screen
private int screenHeight = (getContext().getResources()
.getDisplayMetrics().heightPixels);
private int mX, mY, iX, iY; // current x,y and in
public HomerView(Context context) { // constructor of HomerView
super(context);
System.out.println("Screen Width = "+screenWidth+" and screen height = "+screenHeight);
myBitmap = Bitmap.createBitmap(screenWidth, screenHeight,
Bitmap.Config.ARGB_8888); // set our drawable space - the bitmap which becomes the canvas we draw on
myCanvas = new Canvas(myBitmap); // set our canvas to our bitmap which we just set up
myRect = new Rect(); // make a new rect
myBitmapPaint = new Paint(Paint.DITHER_FLAG); // set dither to ON in our saved drawing - gives better color interaction
}
protected void onDraw(Canvas canvas) { // method used when we want to draw something to our canvas
super.onDraw(canvas);
if (addObjectMode == true || addApplianceMode == true) {
canvas.drawColor(Color.TRANSPARENT); // sets canvas colour
canvas.drawBitmap(myBitmap, 0, 0, myBitmapPaint); // save the canvas to bitmap - the numbers are the x, y coords we are drawing from
for (int i = 0; i < rectList.size(); i++) {
canvas.drawRect(rectList.get(i), myPaint);
}
if (addApplianceMode == true) {
canvas.drawBitmap(bmp, iX-50, iY-50, myBitmapPaint);
}
canvas.drawRect(myRect, myPaint); // draw the rectangle that the user has drawn using the paint we set up
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) { // if screen size changes, alter the bitmap size
super.onSizeChanged(w, h, oldw, oldh);
}
private void touch_Start(float x, float y) { // on finger touchdown
// check touch mode
iX = (int) (Math.round(x));
iY = (int) (Math.round(y));
mX = (int) (Math.round(x));
mY = (int) (Math.round(y));
if (addObjectMode == true) {
myRect.set(iX, iY, mX, mY);
} else if (addApplianceMode == true) {
// code to draw an appliance icon at mX, mY (with offset so icon is centered)
if (isLamp == true) {
Resources res = getResources();
bmp = BitmapFactory.decodeResource(res, R.drawable.lamp);
myCanvas.drawBitmap(bmp, iX - 50, iY - 50, myBitmapPaint);
} else if (isPC == true) {
Resources res = getResources();
bmp = BitmapFactory.decodeResource(res, R.drawable.pc);
myCanvas.drawBitmap(bmp, iX - 50, iY - 50, myBitmapPaint);
} else if (isKettle == true) {
Resources res = getResources();
bmp = BitmapFactory.decodeResource(res, R.drawable.kettle);
myCanvas.drawBitmap(bmp, iX - 50, iY - 50, myBitmapPaint);
} else if (isOven == true) {
Resources res = getResources();
bmp = BitmapFactory.decodeResource(res, R.drawable.oven);
myCanvas.drawBitmap(bmp, iX - 50, iY - 50, myBitmapPaint);
} else if (isTV == true) {
Resources res = getResources();
bmp = BitmapFactory.decodeResource(res, R.drawable.tv);
myCanvas.drawBitmap(bmp, iX - 50, iY - 50, myBitmapPaint);
}
}
}
private void touch_Move(float x, float y) { // on finger movement
float dX = Math.abs(x - mX); // get difference between x and my X
float dY = Math.abs(y - mY);
if (dX >= TOUCH_TOLERANCE || dY >= TOUCH_TOLERANCE) { // if coordinates are outside screen? if touching hard enough?
mX = (int) (Math.round(x));
mY = (int) (Math.round(y));
if (addObjectMode == true) {
myRect.set(iX, iY, mX, mY);
}
}
}
@SuppressWarnings("deprecation")
private void touch_Up() { // on finger release
if (addObjectMode == true) {
myRect.set(iX, iY, mX, mY);
System.out.println("MyRect coords = "+iX+","+iY+","+mX+","+mY);
rectList.add(myRect);
myCanvas.drawRect(iX, iY, mX, mY, myPaint); // if this isnt present - no lasting copy is drawn to screen. It is erased every draw.
if (eraseMode == false) {
dialogStarter();
}
} else if (addApplianceMode == true) {
showDialog(DIALOG_DEVICE_ENTRY);
}
}
public boolean onTouchEvent(MotionEvent event) { // on any touch event
if (addObjectMode == true || addApplianceMode == true) {
float x = event.getX(); // get current X
float y = event.getY(); // get current Y
switch (event.getAction()) { // what action is the user performing?
case MotionEvent.ACTION_DOWN: // if user is touching down
touch_Start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE: // if user is moving finger while touched down
touch_Move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP: // if user has released finger
touch_Up();
invalidate();
break;
}
return true;
} else {
return false;
}
}
}
我意识到我需要添加很多东西 - 但它们是什么？ awakenScrollBars()?
另外：目前我在 XML 文件中收到此错误 Error inflating class com.example.HomerProject1stDraft.DrawNewPlans.HomerView。我创建自定义视图的方式是否有错误？您甚至可以从内部类创建视图吗？
非常感谢。
【问题讨论】：
标签： android xml inner-classes android-custom-view android-scrollview