Android之利用TextWatcher制作自定义编辑文本框

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自定义编辑文本框怎么造呢?

利用Textwatcher观察者来自定义。

首先，我们看下代码：

<span style="font-size:18px;">package com.example.boom.messageproject.ui;import android.content.Context;import android.graphics.drawable.Drawable;import android.text.Editable;import android.text.TextWatcher;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.widget.EditText;import com.example.boom.messageproject.R;/** * Created by Boom on 2016/8/2. */public class CustomEditText extends EditText  {    Context mcontext;    Drawable img;    public CustomEditText(Context context) {        this(context, null);    }    public CustomEditText(Context context, AttributeSet attrs) {        super(context, attrs);        mcontext = context;        init();    }    private void init() {        this.img = mcontext.getResources().getDrawable(R.mipmap.icon_clear);        this.setSingleLine(true);        this.addTextChangedListener(new CustomTextWatcher());        this.setOnFocusChangeListener(new OnFocusChangeListener() {            @Override            public void onFocusChange(View v, boolean hasFocus) {                setDrawable(hasFocus);            }        });    }    class CustomTextWatcher implements TextWatcher {        @Override        public void beforeTextChanged(CharSequence s, int start, int count, int after) {        }        @Override        public void onTextChanged(CharSequence s, int start, int before, int count) {        }        @Override        public void afterTextChanged(Editable s) {            setDrawable(true);        }    }    private void setDrawable(boolean hasFouce) {        if (length() >= 1 && hasFouce) {            setCompoundDrawablesWithIntrinsicBounds(null, null, img, null);        } else {            setCompoundDrawablesWithIntrinsicBounds(null, null, null, null);            ;        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        final int DRAWABLE_RIGHT = 2;        Drawable rightIcon = getCompoundDrawables()[DRAWABLE_RIGHT];        if (rightIcon != null && event.getAction() == MotionEvent.ACTION_UP) {            int leftEdgeOfRightDrawable = getRight() - getPaddingRight()                    - rightIcon.getBounds().width();            if (event.getRawX() >= leftEdgeOfRightDrawable) {                setText("");            }        }        return super.onTouchEvent(event);    }    @Override    protected void finalize() throws Throwable {        img = null;        super.finalize();    }}</span>

功能性代码：

1.设置自定义观察者并添加监察者

<span style="font-size:18px;"> class CustomTextWatcher implements TextWatcher {        @Override        public void beforeTextChanged(CharSequence s, int start, int count, int after) {        }        @Override        public void onTextChanged(CharSequence s, int start, int before, int count) {        }        @Override        public void afterTextChanged(Editable s) {            setDrawable(true);        }    }</span>

<span style="font-size:18px;"> this.addTextChangedListener(new CustomTextWatcher());</span>

2.设置图片位置的显示与不显示，同时包括切换焦点

<span style="font-size:18px;">private void setDrawable(boolean hasFouce) {        if (length() >= 1 && hasFouce) {            setCompoundDrawablesWithIntrinsicBounds(null, null, img, null);        } else {            setCompoundDrawablesWithIntrinsicBounds(null, null, null, null);            ;        }    }</span>

<span style="font-size:18px;">        this.setOnFocusChangeListener(new OnFocusChangeListener() {            @Override            public void onFocusChange(View v, boolean hasFocus) {                setDrawable(hasFocus);            }        });</span>

3.处理点击删除图片删除编辑框的内容

<span style="font-size:18px;">  @Override    public boolean onTouchEvent(MotionEvent event) {        final int DRAWABLE_RIGHT = 2;        Drawable rightIcon = getCompoundDrawables()[DRAWABLE_RIGHT];        if (rightIcon != null && event.getAction() == MotionEvent.ACTION_UP) {            int leftEdgeOfRightDrawable = getRight() - getPaddingRight()                    - rightIcon.getBounds().width();            if (event.getRawX() >= leftEdgeOfRightDrawable) {                setText("");            }        }        return super.onTouchEvent(event);    }</span>

效果图：

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