搜索图标居中的搜索框~iOS风格搜索框

原文：http://www.bkjia.com/Androidjc/1012884.html

自定义EditText实现类iOS风格搜索框，edittextios

最近在项目中有使用到搜索框的地方，由于其样式要求与iOS的UISearchBar的风格一致。默认情况下，搜索图标和文字是居中的，在获取焦点的时候，图标和文字左移。但是在Android是并没有这样的控件（可能见识少，并不知道有）。通常情况下我们使用组合控件，使用ReleativeLayout或者FrameLayout来实现。此篇并不是使用上述方法实现，其核心是继承系统EditText，重写onDraw方法，来改变默认的左上右下的drawable，实现平移到中间位置。这里暂时只实现了drawableLeft的情况，后续将对其进行更新。先来看看实现效果图： 


 

直接来看代码实现

package com.jinlin.custom.iconcenterview;

import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends BaseActivity{
private EditText et_search;

private IconCenterEditText icet_search;

@Override
public void iniView() {
setContentView(R.layout.activity_main);

et_search = (EditText) findViewById(R.id.et_search);
icet_search = (IconCenterEditText) findViewById(R.id.icet_search);

// 实现TextWatcher监听即可
icet_search.setOnSearchClickListener(new IconCenterEditText.OnSearchClickListener() {
@Override
public void onSearchClick(View view) {
Toast.makeText(MainActivity.this, "i'm going to seach", Toast.LENGTH_SHORT).show();
}
});
}
}

这是主Activity的代码，其继承自BaseActivity基类，BaseActivity的实现详细见上篇博文Android点击空白区域，隐藏输入法软键盘只是在isShouldHideKeyboard(View v, MotionEvent event)方法内部增加一行v.clearFocus();代码进行去除焦点处理，其他均一致。

private boolean isShouldHideKeyboard(View v, MotionEvent event) {
if (v != null && (v instanceof EditText)) {
int[] l = {0, 0};
v.getLocationInWindow(l);
int left = l[0],
top = l[1],
bottom = top + v.getHeight(),
right = left + v.getWidth();
if (event.getX() > left && event.getX() < right
&& event.getY() > top && event.getY() < bottom) {
// 点击EditText的事件，忽略它。
return false;
} else {
v.clearFocus();
return true;
}
}
// 如果焦点不是EditText则忽略，这个发生在视图刚绘制完，第一个焦点不在EditText上，和用户用轨迹球选择其他的焦点
return false;
}

接下来是自定义View的代码实现

IconCenterEditText.java

package com.jinlin.custom.iconcenterview;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;

/**
* Created by J!nl!n on 2015/1/26.
*/
public class IconCenterEditText extends EditText implements View.OnFocusChangeListener, View.OnKeyListener {
private static final String TAG = IconCenterEditText.class.getSimpleName();
/**
* 是否是默认图标再左边的样式
*/
private boolean isLeft = false;
/**
* 是否点击软键盘搜索
*/
private boolean pressSearch = false;
/**
* 软键盘搜索键监听
*/
private OnSearchClickListener listener;

public void setOnSearchClickListener(OnSearchClickListener listener) {
this.listener = listener;
}

public IconCenterEditText(Context context) {
this(context, null);
init();
}

public IconCenterEditText(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.editTextStyle);
init();
}

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

private void init() {
setOnFocusChangeListener(this);
setOnKeyListener(this);
}

@Override
protected void onDraw(Canvas canvas) {
if (isLeft) { // 如果是默认样式，则直接绘制
super.onDraw(canvas);
} else { // 如果不是默认样式，需要将图标绘制在中间
Drawable[] drawables = getCompoundDrawables();
if (drawables != null) {
Drawable drawableLeft = drawables[0];
if (drawableLeft != null) {
float textWidth = getPaint().measureText(getHint().toString());
int drawablePadding = getCompoundDrawablePadding();
int drawableWidth = drawableLeft.getIntrinsicWidth();
float bodyWidth = textWidth + drawableWidth + drawablePadding;
canvas.translate((getWidth() - bodyWidth - getPaddingLeft() - getPaddingRight()) / 2, 0);
}
}
super.onDraw(canvas);
}
}

@Override
public void onFocusChange(View v, boolean hasFocus) {
Log.d(TAG, "onFocusChange execute");
// 恢复EditText默认的样式
if (!pressSearch && TextUtils.isEmpty(getText().toString())) {
isLeft = hasFocus;
}
}

@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
pressSearch = (keyCode == KeyEvent.KEYCODE_ENTER);
if (pressSearch && listener != null) {
/*隐藏软键盘*/
InputMethodManager imm = (InputMethodManager) v.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
if (imm.isActive()) {
imm.hideSoftInputFromWindow(v.getApplicationWindowToken(), 0);
}
listener.onSearchClick(v);
}
return false;
}

public interface OnSearchClickListener {
void onSearchClick(View view);
}

}

此View重写onDraw(Canvas canvas)方法，并实现OnFocusChangeListener, OnKeyListener监听接口，在onFocusChange(View v, boolean hasFocus)方法判断是否需要恢复样式，然后在onDraw(Canvas canvas)进行重绘，实现焦点失去和获取时，平移图标和文字。同时还会判断软键盘搜索键的操作进行处理。其核心代码也就是一下这一小段：

Drawable[] drawables = getCompoundDrawables();
if (drawables != null) {
Drawable drawableLeft = drawables[0];
if (drawableLeft != null) {
float textWidth = getPaint().measureText(getHint().toString());
int drawablePadding = getCompoundDrawablePadding();
int drawableWidth = drawableLeft.getIntrinsicWidth();
float bodyWidth = textWidth + drawableWidth + drawablePadding;
canvas.translate((getWidth() - bodyWidth - getPaddingLeft() - getPaddingRight()) / 2, 0);
}
}

activity_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:focusableInTouchMode="true"
android:orientation="vertical"
android:padding="@dimen/activity_vertical_margin"
tools:context=".MainActivity">

<TextView
style="@style/StyleTextView"
android:text="默认样式" />

<EditText
android:id="@+id/et_search"
style="@style/StyleEditText" />

<TextView
style="@style/StyleTextView"
android:text="居中样式" />

<com.jinlin.custom.iconcenterview.IconCenterEditText
android:id="@+id/icet_search"
style="@style/StyleEditText" />

</LinearLayout>

bg_search_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="@android:color/white" />
<stroke
android:width="1px"
android:color="@android:color/darker_gray" />
<corners android:radius="3dp" />
</shape>

styles.xml

<resources>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
</style>

<style name="StyleEditText">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:background">@drawable/bg_search_bar</item>
<item name="android:drawablePadding">5dp</item>
<item name="android:drawableStart">@mipmap/icon_search</item>
<item name="android:gravity">center_vertical</item>
<item name="android:imeOptions">actionSearch</item>
<item name="android:padding">5dp</item>
<item name="android:singleLine">true</item>
<item name="android:textColorHint">@color/gray_white</item>
<item name="android:textSize">16sp</item>
<item name="android:hint">搜索</item>
</style>

<style name="StyleTextView">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">40dp</item>
<item name="android:gravity">center</item>
<item name="android:textSize">20sp</item>
</style>

</resources>

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="gray_white">#ffcccccc</color>
</resources>