Android之利用TextWatcher制作自定义编辑文本框

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 = getCompoundDrawabl
a820
es()[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：