概述：我试图创建一些简单的形状（正方形和三角形），然后将它们用作活动的背景图像。形状的大小取决于屏幕的宽度和高度。问题是，即使我设置了这些形状的边界，它们都被绘制得尽可能大，同时仍然适合屏幕内部。
详细信息：我正在尝试在一个名为ControlsOverlayView.java的重写视图类中创建一个非常简单的背景图像，其上有几个形状。我正在弄清楚画布的大小，然后在onDraw方法中调用我的paint方法，因为这是我第一次知道画布有多大。我通过逐步完成每个形状具有正确边界的代码进行了双重检查，但问题是没有一个形状符合它们的边界，并且每个形状都绘制得尽可能大到可能出现在屏幕上。
public class ControlsOverlayView extends View{
// graphical constants
private static int SIDE_ARROW_WIDTH;
...
...
public ControlsOverlayView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onDraw(Canvas canvas) {
resize(canvas.getWidth(), canvas.getHeight());
paintControls();
super.onDraw(canvas);
}
private void resize(int width, int height) {
// initialize screen size
SCREEN_WIDTH = width;
SCREEN_HEIGHT = height;
HALF_WIDTH = SCREEN_WIDTH / 2;
HALF_HEIGHT = SCREEN_HEIGHT / 2;
SIDE_ARROW_HEIGHT = SCREEN_WIDTH/6;
SIDE_ARROW_WIDTH = SIDE_ARROW_HEIGHT/2;
// calculate constants
TEXT_FONT_HEIGHT = Utils.Font_getHeight(TEXT_FONT);
SCREEN_FRAMED_WIDTH = SCREEN_WIDTH-(2*FRAME_SIZE);
SCREEN_FRAMED_HEIGHT = SCREEN_HEIGHT-(2*FRAME_SIZE);
}
// Creates a background drawable for the control layout including the different coloured panels and the next page arrows
public void paintControls(){
// Calculated layout values
int panelWidth = SIDE_ARROW_WIDTH*3, textViewHeight = (SCREEN_HEIGHT-SIDE_ARROW_HEIGHT)/2;
int leftArrowX = (SCREEN_WIDTH/8)+(SIDE_ARROW_WIDTH/3), rightArrowX = SCREEN_WIDTH-(SCREEN_WIDTH/4)+(SCREEN_WIDTH/8)-(SIDE_ARROW_WIDTH/3), arrowY = (SCREEN_HEIGHT/2)-(SIDE_ARROW_HEIGHT/2);
// Rect array that stores the bounds of each layer of the background
Rect [] bounds = new Rect[3];
int i = 0;
// background
ShapeDrawable background = new ShapeDrawable(new RectShape());
bounds[i++] = new Rect(0,0,SCREEN_WIDTH,SCREEN_HEIGHT);
background.getPaint().setColor(CONTROLS_BACKGROUND_COLOR);
// left panel
ShapeDrawable leftPanel = new ShapeDrawable(new RectShape());
bounds[i++] = new Rect(0, 0, panelWidth, SCREEN_HEIGHT);
leftPanel.getPaint().setColor(CONTROLS_PANEL_COLOR);
// right arrow
Path rightArrowPath = new Path();
rightArrowPath.moveTo(SIDE_ARROW_WIDTH, SIDE_ARROW_HEIGHT/2);
rightArrowPath.lineTo(0, SIDE_ARROW_HEIGHT);
rightArrowPath.lineTo(0, 0);
rightArrowPath.lineTo(SIDE_ARROW_WIDTH, SIDE_ARROW_HEIGHT/2);
rightArrowPath.close();
ShapeDrawable rightArrow = new ShapeDrawable(new PathShape(rightArrowPath, SIDE_ARROW_WIDTH, SIDE_ARROW_HEIGHT));
bounds[i++] = new Rect(rightArrowX, arrowY, rightArrowX+SIDE_ARROW_WIDTH, arrowY+SIDE_ARROW_HEIGHT);
rightArrow.getPaint().setColor(CONTROLS_ARROW_COLOR);
Drawable [] layers = new Drawable[] { background, leftPanel, rightArrow };
LayerDrawable controlsBackground = new LayerDrawable(layers);
controlsBackground.setBounds(0,0,SCREEN_WIDTH,SCREEN_HEIGHT);
// set the bounds of each layer
for (i=0;i<controlsBackground.getNumberOfLayers();i++) {
controlsBackground.getDrawable(i).setBounds(bounds[i]);
}
controlsBackground.setAlpha(100);
controlsLayout.setBackgroundDrawable(controlsBackground);
controlsLayout.setVisibility(View.VISIBLE);
}
}
该活动名为ControlsOverlayActivity.java，如下所示：
public class ControlsOverlayActivity extends Activity {
private ControlsOverlayView overlay;
private static WattpadApp appState;
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.controls_overlay);
// initialize the controls overlay
ControlsOverlayView.controlsLayout = (LinearLayout) findViewById(R.id.controls_layout);
ControlsOverlayView.controlsLayout.setOnClickListener(controlsListener);
ControlsOverlayView.controlsTextViews = new TextView[] {
(TextView) findViewById(R.id.controls_text_left_above),
(TextView) findViewById(R.id.controls_text_right_above),
(TextView) findViewById(R.id.controls_text_middle),
(TextView) findViewById(R.id.controls_text_left_below),
(TextView) findViewById(R.id.controls_text_right_below)
};
// initialize the fade in/out animations for the controls overlay
ControlsOverlayView.controlsFadeIn = new AlphaAnimation(0,1);
ControlsOverlayView.controlsFadeIn.setDuration(ControlsOverlayView.CONTROLS_FADE_DURATION);
ControlsOverlayView.controlsFadeOut = new AlphaAnimation(1,0);
ControlsOverlayView.controlsFadeOut.setDuration(ControlsOverlayView.CONTROLS_FADE_DURATION);
ControlsOverlayView.controlsFadeOut.setAnimationListener(new AnimationListener(){
public void onAnimationEnd(Animation animation) {
//ControlsOverlayView.controlsLayout.setVisibility(View.GONE);
}
public void onAnimationRepeat(Animation animation) {}
public void onAnimationStart(Animation animation) {}
});
}
private OnClickListener controlsListener = new OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
};
}
xml文件名为controls_overlay.xml，如下所示：
<?xml version="1.0" encoding="utf-8"?>
<!-- Controls Overlay -->
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/controls_overlay"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<wp.wattpad.ui.ControlsOverlayView
android:layout_width="1dp"
android:layout_height="1dp"
/>
<LinearLayout
android:id="@+id/controls_layout"
android:orientation="horizontal"
android:visibility="invisible"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<!-- Left Panel -->
<LinearLayout
android:orientation="vertical"
android:gravity="left"
android:layout_width="wrap_content"
android:layout_height="fill_parent" >
<TextView android:id="@+id/controls_text_left_above"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal|bottom"
android:text="@string/controls_prevpage" />
<TextView android:id="@+id/controls_text_left_below"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal|top"
android:text="@string/controls_scrollslower" />
</LinearLayout>
<!-- Middle Panel -->
<LinearLayout
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="fill_parent" >
<TextView android:id="@+id/controls_text_middle"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_horizontal|center_vertical"
android:text="@string/taptoscroll" />
</LinearLayout>
<!-- Right Panel -->
<LinearLayout
android:orientation="vertical"
android:gravity="right"
android:layout_width="wrap_content"
android:layout_height="fill_parent" >
<TextView android:id="@+id/controls_text_right_above"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal|bottom"
android:text="@string/controls_nextpage" />
<TextView android:id="@+id/controls_text_right_below"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal|top"
android:text="@string/controls_scrollfaster" />
</LinearLayout>
</LinearLayout>
我真的被困在这里，我想知道是否可能从onDraw（）方法调用resize和paint不是最好的地方，但是我不知道我还能做什么，因为我需要知道屏幕的高度和宽度。我也尝试过调用super.onDraw（），它没有改变任何东西。
答案 0 :(得分：2)
经过几个令人沮丧的时间后找到答案。我使用resize()致电resize(canvas.getWidth(), canvas.getHeight());，应该是controlsLayout.getWidth()和controlsLayout.getHeight()。即使画布高度的高度与视图高度相差几个像素，也完全忽略了边界。不知道为什么会这样，而且非常令人沮丧，但问题已经解决了。