Android，从 EditText 动态更改下划线颜色 [英] Android, change underline Color from an EditText dynamically

问题描述

是否可以动态更改 EditText 中下划线的颜色?就像效果一样，当我聚焦它时，它会变成蓝色.

is it possible to change the color of the underline from a EditText dynamically? Like the effect, when i focus it, then it turns into blue.

希望你明白我想做什么.

Hope you understand what i want to do.

推荐答案

创建您自己的自定义 EditText 控件.

Create your own customized EditText control.

这是我专门为您制作的示例:

Here's an example that I made just for you:

选中后，您只需要将mPaint.setColor(Color.GREEN); 更改为另一种颜色

When selected, you just have to change mPaint.setColor(Color.GREEN); to another color

public class CustomEditText extends EditText {
    private Rect mRect;
    private Paint mPaint;
    int widthMsSize;
    int heightMsSize;
    // we need this constructor for LayoutInflater
    public CustomEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(5);
        mPaint.setColor(Color.GREEN);
        System.out.println("constructor");
    }
    protected void onMeasure(final int widthMeasureSpec,
        final int heightMeasureSpec) {
        // Extract the Ms (MesaureSpec) parameters
        widthMsSize = MeasureSpec.getSize(widthMeasureSpec);
        heightMsSize = MeasureSpec.getSize(heightMeasureSpec);
        System.out.println("on measure");
        // Satisfy contract by calling setMeasuredDimension
        setMeasuredDimension(widthMsSize,
            heightMsSize);
    }
    protected void onDraw(Canvas canvas) {
        canvas.drawLine(5, heightMsSize - 10, widthMsSize - 5, heightMsSize - 10, mPaint); //draw underline
        canvas.drawLine(8, heightMsSize - 10, 8, heightMsSize - 20, mPaint); //draw left corner
        canvas.drawLine(widthMsSize - 8, heightMsSize - 10, widthMsSize - 8, heightMsSize - 20, mPaint); //draw right corner
        super.onDraw(canvas);
    }
}

main.xml

<LinearLayout 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:orientation="vertical" >

    <com.example.testanimationfadeinfadeout.CustomEditText
        android:id="@+id/textedit"
        android:layout_width="228dp"
        android:layout_height="41dp"
        android:ems="10"
        android:hint="color is changed" />

</LinearLayout>

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