Android开发中TextView 实现右上角跟随文本动态追加圆形红点

在一个比较坑的需求里，一段文字右上角需要追加一个圆形红点。最右侧有个金额，红点动态随着文字移动，然后各种摆布局，一下午坑死我了。后来果断放弃。然后就想试试直接自定义view来实现这个需求。

最坑的就是效果下面的第一种情况和第二种情况，就是这两种情况给逼的

废话不说，开搞。

首先自定义个view 继承自 view 类

public class MyViewAndCircle extends View{
}

然后不用说了，直接飘红，必须要实现几个必要的方法了。

 public MyViewAndCircle(Context context) {
    this(context,null);
    // TODO Auto-generated constructor stub
  }
  public MyViewAndCircle(Context context, AttributeSet attrs) {
    this(context, attrs,0);
    // TODO Auto-generated constructor stub
  }
  public MyViewAndCircle(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

然后就要想想这个需求到底是什么鬼了。

因为目前来说需要一个文本，还要有个红色圆形追加到文本域后边，那么有两种考虑了

- 1、文本+画圆

- 2、文本+图片

在这里我选第一种了，毕竟在view里边画个圆还是比较easy的，这种教程网上一搜一大把

那么既然有了目标

就可以写 attrs了，

如上我们定义了==文本自身==， ==文本size==，==文本color==，为什么不定义圆形用的属性。那是因为。。。用不到，画个圆而已嘛，不用那么麻烦

定义完了属性之后那么就要引入了：

public MyViewAndCircle(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    // TODO Auto-generated constructor stub
    TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomMyViewTitle, defStyleAttr, 0);
    int n = a.getIndexCount();
    for (int i = 0; i < n; i++) {
      int attr = a.getIndex(i);
      switch (attr) {
      case R.styleable.CustomMyViewTitle_titleTextview:
 mText = a.getString(attr);
 break;
      case R.styleable.CustomMyViewTitle_titleSizeview:
 mTextSize = a.getDimensionPixelOffset(attr, (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
 break;
      case R.styleable.CustomMyViewTitle_titleColorview:
 mTextColor = a.getInt(attr, Color.BLACK);
 break;
      }
    }
    a.recycle();
  }

至此我们就将定义的控件中用的属性撸出来了，那么下面就开始撸代码了。

我贴个完整代码：代码里都加了注释来着

这个是view的代码：

package com.qiao.view;
import com.qiao.Utils.Utils;
import com.qiao.selfview.R;
import com.qiao.selfview.R.styleable;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.view.View.MeasureSpec;

public class MyViewAndCircle extends View{
  private String mText;//描述文字
  private int mTextColor;//描述文字颜色
  private int mTextSize;//描述文字大小
  private Rect rect;//控制边框 完整控件控制边框显示（宽高之类的）
  private Rect mTextBound;//控制文本范围
  private Rect mCircle;//控制红色圆点的位置
  private Paint mPaint;//控制画笔
  private int mWidth;//宽
  private int mHeight;//高
  private boolean isShow = true;
  RectF oval = null;//控制圆的边界
  public MyViewAndCircle(Context context) {
    this(context,null);
    // TODO Auto-generated constructor stub
  }
  public MyViewAndCircle(Context context, AttributeSet attrs) {
    this(context, attrs,0);
    // TODO Auto-generated constructor stub
  }
  public MyViewAndCircle(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    // TODO Auto-generated constructor stub
    TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomMyViewTitle, defStyleAttr, 0);
    int n = a.getIndexCount();
    for (int i = 0; i < n; i++) {
      int attr = a.getIndex(i);
      switch (attr) {
      case R.styleable.CustomMyViewTitle_titleTextview:
 mText = a.getString(attr);
 break;
      case R.styleable.CustomMyViewTitle_titleSizeview:
 mTextSize = a.getDimensionPixelOffset(attr, (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));
 break;
      case R.styleable.CustomMyViewTitle_titleColorview:
 mTextColor = a.getInt(attr, Color.BLACK);
 break;
      }
    }
    a.recycle();
    mPaint = new Paint();//这里做初始化
    rect = new Rect();
    mTextBound = new Rect();
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    // TODO Auto-generated method stub
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    //在这里测量当前控件的宽和高，具体的意思请看
    
    int specMode = MeasureSpec.getMode(widthMeasureSpec);
    int spenSize = MeasureSpec.getSize(widthMeasureSpec);
    if (specMode ==MeasureSpec.EXACTLY) {
      mWidth = spenSize;
    }
    specMode = MeasureSpec.getMode(heightMeasureSpec);
    spenSize = MeasureSpec.getSize(heightMeasureSpec);
    if (specMode==MeasureSpec.EXACTLY) {
      mHeight = spenSize;
    }else {
      mPaint.setTextSize(16);
      mPaint.getTextBounds(mText, 0, mText.length(), mTextBound);
      float textHeight = mTextBound.height();
      int desired = (int) (getPaddingTop()+textHeight+getPaddingBottom());
      mHeight = desired;
    }
    setMeasuredDimension(mWidth, mHeight);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    //这里就开始执行绘制了
    mPaint.setTextSize(mTextSize);
    mPaint.getTextBounds(mText, 0, mText.length(), mTextBound);//计算文字所需要的宽度
    mPaint.setColor(Color.BLUE);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setTextSize(mTextSize);
    Utils.mLogError("==-->rect.width() "+rect.width());
    rect.left=0;
    rect.top=0;
    rect.right=getMeasuredWidth();
    rect.bottom = getMeasuredHeight();
    canvas.drawRect(rect, mPaint);//这里在绘制最外侧布局的宽高
    mPaint.reset();
    //下面判断文本是否超出了父布局宽，然后分别作了设置
    if (mTextBound.width()>mWidth) {
//     文字超长展示
      mPaint.setTextSize(mTextSize);
      TextPaint paint = new TextPaint(mPaint);
      String msg = TextUtils.ellipsize(mText, paint, (float) mWidth - getPaddingLeft() - getPaddingRight(),
   TextUtils.TruncateAt.END).toString();
      canvas.drawText(msg, getPaddingLeft(), mHeight/2 - getPaddingTop()+mTextBound.height()/2, mPaint);
      mPaint.reset();
      if (isShow) {
 // 控制红色圆形大小
 mPaint.setAntiAlias(true);
 mPaint.setColor(Color.parseColor("#FE4D3D"));
 oval = new RectF();
 oval.left = getMeasuredWidth()-30;
 oval.right=getMeasuredWidth();
 oval.top=getMeasuredHeight()/2 - mTextBound.height()/2 - 30;
 oval.bottom=getMeasuredHeight()/2 - mTextBound.height()/2;
 canvas.drawArc(oval, 0, 360, true, mPaint);
 mPaint.reset();
      }
    }else {
      //正常情况
      mPaint.setTextSize(mTextSize);
      canvas.drawText(mText, getPaddingLeft(), (mHeight/2 - mTextBound.height()/2)+mTextBound.height()-getPaddingBottom(), mPaint);
      mPaint.reset();
      if (isShow) {
 // 控制红色圆形大小
 mPaint.setAntiAlias(true);
 mPaint.setColor(Color.parseColor("#FE4D3D"));
 oval = new RectF();
 oval.left = mTextBound.width()+getPaddingRight();
 oval.right=mTextBound.width()+getPaddingRight()+30;
 oval.top=getMeasuredHeight()/2 - mTextBound.height()/2 - 30;
 oval.bottom=getMeasuredHeight()/2 - mTextBound.height()/2;
 canvas.drawArc(oval, 0, 360, true, mPaint);
 mPaint.reset();
      }
    }
  }
  public void setTitleText(String mText){
    this.mText = mText;
  }
  public void setIsVisiable(boolean isShow){
    this.isShow = isShow;
  }
  public void notification(){
    invalidate();
  }
}

这个是activity界面：

package com.qiao.selfview;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import com.qiao.base.baseActivity;
import com.qiao.view.MyViewAndCircle;
public class MySelfView extends baseActivity{
  private Button button_show;
  private Button button_show_one;
  private Button button_show_circle;
  private Button button_show_circle_no;
  private MyViewAndCircle textView;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_myselfview);
    textView = (MyViewAndCircle) findViewById(R.id.textView);
    button_show_one = (Button) findViewById(R.id.button_show_one);
    button_show = (Button) findViewById(R.id.button_show);
    button_show_circle = (Button) findViewById(R.id.button_show_circle);
    button_show_circle_no = (Button) findViewById(R.id.button_show_circle_no);
    button_show_one.setonClickListener(new onClickListener() {
      @Override
      public void onClick(View v) {
 // TODO Auto-generated method stub
 textView.setTitleText("收拾收拾");
 textView.notification();
      }
    });
    button_show.setonClickListener(new onClickListener() {
      @Override
      public void onClick(View v) {
 // TODO Auto-generated method stub
 textView.setTitleText("我的天呐这个不科学，是不是，你说是不是，我说是的,我的天呐。这个东西是个什么鬼。啥玩意？？？？？？？？？？？？？？？？");
 textView.notification();
      }
    });
    button_show_circle.setonClickListener(new onClickListener() {
      @Override
      public void onClick(View v) {
 // TODO Auto-generated method stub
 textView.setIsVisiable(true);
 textView.notification();
      }
    });
    button_show_circle_no.setonClickListener(new onClickListener() {
      @Override
      public void onClick(View v) {
 // TODO Auto-generated method stub
 textView.setIsVisiable(false);
 textView.notification();
      }
    });
  }
}

这个当然就是activity布局了：

以上所述是小编给大家介绍的Android开发中TextView 实现右上角跟随文本动态追加圆形红点，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对考高分网网站的支持！

Android开发中TextView 实现右上角跟随文本动态追加圆形红点

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