EditText 集锦 - 开发中常用的用法及遇到的各种坑

 /**
     * EditText获取焦点并显示软键盘
     */
    public static void showSoftInputFromWindow(Activity activity, EditText editText) {
        editText.setFocusable(true);
        editText.setFocusableInTouchMode(true);
        editText.requestFocus();
        //显示软键盘
        activity.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
        //如果上面的代码没有弹出软键盘 可以使用下面另一种方式
        //InputMethodManager imm = (InputMethodManager) activity.getSystemService(Context.INPUT_METHOD_SERVICE);
       // imm.showSoftInput(editText, 0); 
    }

android:focusable="true" 
android:focusableInTouchMode="true"

<RelativeLayout 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:focusable="true"
    android:focusableInTouchMode="true"
    ><!-- 这两句是为了取消自动获取焦点 -->

     <EditText
         android:id="@+id/search_edittext"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:layout_marginTop="15dp"
         android:background="@drawable/search_bar_edit_bg"
         android:drawableLeft="@drawable/search_bar_icon_normal"
        
         android:hint="搜索"
         android:selectAllOnFocus="true"
         android:singleLine="true"
		 
</RelativeLayout>

mEt.setOnKeyListener(new View.OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_UP) {
            Log.i(TAG, "手指弹起时执行确认功能");
            return true;
        }

        return false;
    }
});

mInputEditTxt.addTextChangedListener(new 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) {
			Log.i(TAG, "监听EditText输入内容的变化，在这里可以监听输入内容的长度。");
		}

		@Override
		public void afterTextChanged(Editable s) {
				Log.i(TAG, "这里可以实现所输即所得，用户输入的同时可以立即在这里根据输入内容执行操作，显示搜索结果！");
		}
	});

public static final int MAX_LEN = 30;

if (!TextUtils.isEmpty(mValue)) {
    int len = Math.min(mValue.length(), MAX_LEN);
    mValue = mValue.substring(0, len);
    mEtText.setText(mValue);
    mEtText.setSelection(mValue.length());
}

mEtText.addTextChangedListener(new 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) {
        Editable text = mEtText.getText();
        if (TextUtils.isEmpty(text)) {
            return;
        }

        if (text.length() > MAX_LEN) {
            mEtText.setText(text.subSequence(0, MAX_LEN));
            mEtText.setSelection(mEtText.getText().length());
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});

public class InputTxtFilter{
	public static final int INPUT_TYPE_EN = 0x01;
	public static final int INPUT_TYPE_CH = 0x02;
    private static final String[] SPELL = new String[]{
    	"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",
    	"ā","á","ǎ","à","ō","ó","ǒ","ò","ē","é","ě","è","ī","í","ǐ","ì","ū","ú","ǔ","ù","ǖ","ǘ","ǚ","ǜ","ü"
    };
    private static char[] chineseParam = new char[]{'」','，','。','？','…','：','～','【','＃','、','％','＊','＆','＄','（','‘','’','“','”','『','〔','｛','【'
    	,'￥','￡','‖','〖','《','「','》','〗','】','｝','〕','』','”','）','！','；','—'};
    
    private InputTxtFilter( ){
    	
    }
    
	public static void inputFilter( final Context context, final EditText editText, final int type, final int inputLimit){
		InputFilter[] filters = new InputFilter[1];
		filters[0] = new InputFilter.LengthFilter(inputLimit){
			public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend){
				boolean isRightCharater = false;
				if(type == INPUT_TYPE_EN){
					isRightCharater = isLetter(source.toString());
				}else if(type == INPUT_TYPE_CH){
					isRightCharater = isChineseWord(source.toString());
				}
				
				if ( !isRightCharater|| dest.toString( ).length( )>=inputLimit ){
					return "";
				}

				return source;
			}
		};
		editText.setFilters(filters);
	}
	
	/**
     * 检测String是否全是中文
     * 
     */
	public static boolean isChineseWord( String name ){
		boolean res=true;
		char[] cTemp = name.toCharArray( );
		
		for( int i = 0; i < name.length( ); i++ ){
			if( !isChinese( cTemp[ i ] ) ){
				res=false;
				break;
			}
		}
		
		return res;
	}
	
	/**
	 * 是否为英文字母
	 * 
	 * */
	public static boolean isLetter( String inputStr ){
		char[] inputArray = inputStr.toCharArray( );
		List<String> spellList = Arrays.asList( SPELL );
		
		for( char input : inputArray ){
			if( !spellList.contains( input + "" ) ){
				return false;
			}
		}
		
		return true;
	}
	
	/**
	 * 判定输入汉字
	 * @param c
	 */
    public static boolean isChinese( char c ){
    	for( char param : chineseParam ){
        	if( param == c ){
        		return false;
        	}
        }
    	
        Character.UnicodeBlock ub = Character.UnicodeBlock.of( c );
        if ( ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
            || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
            || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
            || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
            || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
            || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS ){
            return true;
        }
        
        return false;
    }
}

**InputTxtFilter.inputFilter(this, mInputEditTxt, InputTxtFilter.INPUT_TYPE_EN, 5);**

 //从密码不可见模式变为密码可见模式（行得通）
et_password.setInputType(InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD);
//从密码可见模式变为密码不可见模式（行不通）
 et_password.setInputType(InputType.TYPE_TEXT_VARIATION_PASSWORD);

//从密码不可见模式变为密码可见模式
et_password.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
 //从密码可见模式变为密码不可见模式
et_password.setTransformationMethod(PasswordTransformationMethod.getInstance())