以编程方式绘制气泡

I would like to have a bubble with a precentage value in my app, I can't use 9 patches as i want it to be customizable and its background color should be changeble. It should look something like this

我该怎么做？这个气泡内部的视图会膨胀，比如这个百分比或一些更大的布局。 另外，根据布局（手机或平板电脑），它的一侧可能比另一侧大（箭头不在中心），所以这是我更喜欢以编程方式执行此操作的另一个原因

创建一个自定义 Drawable 并将其用作您要放入文本或其他视图的任何容器的背景。
您将需要修改背景的填充以考虑气泡的指针。
下面的代码允许您将指针的对齐方式设置为左对齐、居中对齐或右对齐。
这只是一个基本版本，仅供您参考。您可以轻松地添加气泡颜色的设置器，或者向“mPaint”添加描边属性以获得额外的灵活性。

public class BubbleDrawable extends Drawable {

    // Public Class Constants
    ////////////////////////////////////////////////////////////

    public static final int LEFT = 0;
    public static final int CENTER = 1;
    public static final int RIGHT = 2;

    // Private Instance Variables
    ////////////////////////////////////////////////////////////

    private Paint mPaint;
    private int mColor;

    private RectF mBoxRect;
    private int mBoxWidth;
    private int mBoxHeight;
    private float mCornerRad;
    private Rect mBoxPadding = new Rect();

    private Path mPointer;
    private int mPointerWidth;
    private int mPointerHeight;
    private int mPointerAlignment;

    // Constructors
    ////////////////////////////////////////////////////////////

    public BubbleDrawable(int pointerAlignment) {
        setPointerAlignment(pointerAlignment);
        initBubble();
    }

    // Setters
    ////////////////////////////////////////////////////////////

    public void setPadding(int left, int top, int right, int bottom) {
        mBoxPadding.left = left;
        mBoxPadding.top = top;
        mBoxPadding.right = right;
        mBoxPadding.bottom = bottom;
    }

    public void setCornerRadius(float cornerRad) {
        mCornerRad = cornerRad;
    }

    public void setPointerAlignment(int pointerAlignment) {
        if (pointerAlignment < 0 || pointerAlignment > 3) {
            Log.e("BubbleDrawable", "Invalid pointerAlignment argument");
        } else {
            mPointerAlignment = pointerAlignment;
        }
    }

    public void setPointerWidth(int pointerWidth) {
        mPointerWidth = pointerWidth;
    }

    public void setPointerHeight(int pointerHeight) {
        mPointerHeight = pointerHeight;
    }

    // Private Methods
    ////////////////////////////////////////////////////////////

    private void initBubble() {
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mColor = Color.RED;
        mPaint.setColor(mColor);
        mCornerRad = 0;
        setPointerWidth(40);
        setPointerHeight(40);
    }

    private void updatePointerPath() {
        mPointer = new Path();
        mPointer.setFillType(Path.FillType.EVEN_ODD);

        // Set the starting point
        mPointer.moveTo(pointerHorizontalStart(), mBoxHeight);

        // Define the lines
        mPointer.rLineTo(mPointerWidth, 0);
        mPointer.rLineTo(-(mPointerWidth / 2), mPointerHeight);
        mPointer.rLineTo(-(mPointerWidth / 2), -mPointerHeight);
        mPointer.close();
    }

    private float pointerHorizontalStart() {
        float x = 0;
        switch (mPointerAlignment) {
        case LEFT:
            x = mCornerRad;
            break;
        case CENTER:
            x = (mBoxWidth / 2) - (mPointerWidth / 2);
            break;
        case RIGHT:
            x = mBoxWidth - mCornerRad - mPointerWidth;
        }
        return x;
    }

    // Superclass Override Methods
    ////////////////////////////////////////////////////////////

    @Override
    public void draw(Canvas canvas) {
        mBoxRect = new RectF(0.0f, 0.0f, mBoxWidth, mBoxHeight);
        canvas.drawRoundRect(mBoxRect, mCornerRad, mCornerRad, mPaint);
        updatePointerPath();
        canvas.drawPath(mPointer, mPaint);
    }

    @Override
    public int getOpacity() {
        return 255;
    }

    @Override
    public void setAlpha(int alpha) {
        // TODO Auto-generated method stub

    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        // TODO Auto-generated method stub

    }

    @Override
    public boolean getPadding(Rect padding) {
        padding.set(mBoxPadding);

        // Adjust the padding to include the height of the pointer
        padding.bottom += mPointerHeight;
        return true;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        mBoxWidth = bounds.width();
        mBoxHeight = getBounds().height() - mPointerHeight;
        super.onBoundsChange(bounds);
    }
}

Usage
下面的示例展示了如何使用 BubbleDrawable。

MainActivity.java

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LinearLayout linearLayout = (LinearLayout)findViewById(R.id.myLayout);
        BubbleDrawable myBubble = new BubbleDrawable(BubbleDrawable.CENTER);
        myBubble.setCornerRadius(20);
        myBubble.setPointerAlignment(BubbleDrawable.RIGHT);
        myBubble.setPadding(25, 25, 25, 25);
        linearLayout.setBackgroundDrawable(myBubble);
    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <LinearLayout
        android:id="@+id/myLayout"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Some Text"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Some Other Text"
            android:textAppearance="?android:attr/textAppearanceLarge" />
        </LinearLayout>

</RelativeLayout>