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概述：我嘗試創建一些簡單的形狀（正方形和三角形），然後將它們用作活動的背景圖像。形狀的大小取決於屏幕的寬度和高度。問題在於，儘管我正在設置這些形狀的邊界，但它們仍然儘可能大，同時仍然適合屏幕內部。何處在自定義視圖中設置繪圖的邊界
詳細信息：我想創建一個非常簡單的背景圖像，其中包含一些形狀的重載視圖類，名爲Controlsoverviewview.java。我計算出畫布的大小，然後在onDraw方法中調用我的paint方法，因爲這是我第一次知道畫布的大小。我仔細檢查了每個形狀都有正確邊界的代碼，但問題是沒有一個形狀服從它們的邊界，並且每個形狀的繪製都儘可能大，因爲它可能會出現在屏幕上。
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);
}
}
活動被稱爲ControlsOverlayActivity.java，看起來像：
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();
}
};
}
和XML文件被稱爲controls_overlay.xml，看起來像：
<?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>
我真的被卡在這裏，我想知道是否可能調用調整大小和從onDraw（）方法繪製不是最好的地方做，但我不知道我可以做到這一點，因爲我需要知道的高度和屏幕寬度。我也嘗試過對super.onDraw（）的調用，它沒有改變任何東西。