我要画一条虚线。我现在用这个来画实线:

LinearLayout divider = new LinearLayout( this );
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams( LinearLayout.LayoutParams.FILL_PARENT, 2 );
divider.setLayoutParams( params );
divider.setBackgroundColor( getResources().getColor( R.color.grey ) );

我需要这样的东西,但不是实心的,而是虚线的。我想避免在透明布局和固体布局之间交替制作数百个布局。


当前回答

如果你正在寻找一条垂直线使用这个绘图。

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:top="-8dp"
        android:bottom="-8dp"
        android:left="-8dp">
        <shape>
            <solid android:color="@android:color/transparent"/>
            <stroke
                android:width="4dp"
                android:color="#ffffff"
                android:dashGap="4dp"
                android:dashWidth="4dp"/>
        </shape>
    </item>
</layer-list>

顶部、底部和左侧的负值删除形状不需要的边,只留下一条虚线。

在视图中使用它。

<View
android:layout_width="4dp"
android:layout_height="match_parent"
android:background="@drawable/dash_line_vertical"
android:layerType="software" />

其他回答

唯一对我有用的方法,我认为这是最简单的方法,就是使用Path和一个paint对象,就像这样:

    Paint paintDash = new Paint();
    paintDash.setARGB(255, 0, 0, 0);
    paintDash.setStyle(Paint.Style.STROKE);
    paintDash.setPathEffect(new DashPathEffect(new float[]{10f,10f}, 0));
    paintDash.setStrokeWidth(2);
    Path pathDashLine = new Path();

然后onDraw():(重要调用重置,如果你改变这些点之间的onDraw调用,导致路径保存所有的移动)

    pathDashLine.reset();
    pathDashLine.moveTo(porigenX, porigenY);
    pathDashLine.lineTo(cursorX,cursorY);
    c.drawPath(pathDashLine, paintDash);

我不知道为什么,但投票的答案不适合我。我这样写,效果很好。 定义一个自定义视图:

public class XDashedLineView extends View {

private Paint   mPaint;
private Path    mPath;
private int     vWidth;
private int     vHeight;

public XDashedLineView(Context context) {
    super(context);
    init();
}

public XDashedLineView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
}

public XDashedLineView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init();
}

private void init() {
    mPaint = new Paint();
    mPaint.setColor(Color.parseColor("#3F577C"));
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setPathEffect(new DashPathEffect(new float[] {10,10}, 0));
    mPath = new Path();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    this.vWidth = getMeasuredWidth();
    this.vHeight = getMeasuredHeight();
    mPath.moveTo(0, this.vHeight / 2);
    mPath.quadTo(this.vWidth / 2, this.vHeight / 2, this.vWidth, this.vHeight / 2);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawPath(mPath, mPaint);
}
}

然后你可以在你的xml中使用它:

        <com.YOUR_PACKAGE_NAME.XDashedLineView
        android:layout_width="690dp"
        android:layout_height="1dp"
        android:layout_marginLeft="30dp"
        android:layout_marginTop="620dp"/>

类似于777,这里有一个水平线的解决方案:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:top="-1dp">
        <shape android:shape="line">
            <stroke
                android:width="1dp"
                android:color="#111"
                android:dashWidth="8dp"
                android:dashGap="2dp"
                />
            <solid android:color="@android:color/transparent" />
        </shape>
    </item>
</layer-list>

线索是<item android:top="-1dp">。

为了在旧设备上显示虚线(<= API 21),你应该用android:layerType="software"创建一个视图(见android虚线可绘制潜在ICS错误):

<?xml version="1.0" encoding="utf-8"?>
<View xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="@drawable/dashed_line"
    android:layerType="software"
    />

你也可以在没有android:layerType="software"的情况下添加相同的视图到layout-v23,以获得更好的性能,但我不确定它是否适用于所有具有API 23的设备。

创建xml (view_line_dot .xml):

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
        <item
            android:bottom="-1dp"
            android:left="-1dp"
            android:right="-1dp"
            android:top="0dp">

            <shape android:shape="rectangle">
                <stroke
                    android:width="1dp"
                    android:color="#ffff0017"
                    android:dashGap="3dp"
                    android:dashWidth="1dp" />

                <solid android:color="@android:color/transparent" />

                <padding
                    android:bottom="10dp"
                    android:left="10dp"
                    android:right="10dp"
                    android:top="10dp" />
            </shape>
        </item>
</layer-list>

设置为视图背景:

<View
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:background="@drawable/view_line_dotted" />

我使用下面的作为布局的背景:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle">
<stroke
   android:width="1dp"
    android:dashWidth="10px"
   android:dashGap="10px"
    android:color="android:@color/black" 
   />
</shape>