android 焦点控制及运用

setFocusable()   设置view接受焦点的资格   
isFocusable()    view是否具有接受焦点的资格  

setFocusInTouchMode()      对应在触摸模式下,设置是否有焦点来响应点触的资格         
isFocusableInTouchMode()  对应在触摸模式下,view是否具有焦点的资格

强制view焦点获取，注意：这些方法都不会触发事件（onTouch，onClick等），想要触发onClick事件请调用view.performClick()
requestFocus()                                 ------ view
requestFocus(int direction)当用户在某个界面聚集焦点,参数为下面的4个
requestFocusFromTouch()    触摸模式下
  ......
requestChildFocus (View child, View focused)   ------viewGroup
1 父元素调用此方法
2 child  将要获取焦点的子元素
3 focused 现在拥有焦点的子元素

一般也可以通过 配置文件设置
View.FOCUS_LEFT     Move focus to the left
View.FOCUS_UP       Move focus up
View.FOCUS_RIGHT    Move focus to the right
View.FOCUS_DOWN     Move focus down            
代码设置实现 其实都是通过这些设置的        

isInTouchMode()    触摸模式

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下面的例子主要使用了requestFocus()方法使焦点在各个控件之间切换。
看下图：



最上面的弹出框是个PopupWindow，需要依次输入4个密码，为了方便快捷，当上一个文本框输入值之后，焦点自动切换到下一个文本框，当输入到最后一个文本框后，PopupWindow自动关闭，并返回4个文本框中的值，放在String[]数组中。
看代码：

package com.reyo.view;

import android.content.Context;
import android.graphics.drawable.BitmapDrawable;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.LinearLayout.LayoutParams;
import android.widget.PopupWindow;

import com.reyo.merchant2.R;

public class PasswordPopupWindow extends PopupWindow {

	private Context context;
	private EditText[] texts;
	private ImageButton btn_close;

	public PasswordPopupWindow(Context context, View view) {
		super(view, LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, true);
		this.context = context;
		this.setBackgroundDrawable(new BitmapDrawable());// 响应返回键，响应触摸周边消失
		this.setAnimationStyle(R.style.PopupAnimationFromTop);
		this.setInputMethodMode(PopupWindow.INPUT_METHOD_FROM_FOCUSABLE);
		texts = new EditText[4];
		texts[0] = (EditText) view.findViewById(R.id.et_0);
		texts[1] = (EditText) view.findViewById(R.id.et_1);
		texts[2] = (EditText) view.findViewById(R.id.et_2);
		texts[3] = (EditText) view.findViewById(R.id.et_3);
		for (int i = 0; i < texts.length; i++) {
			final int curIndex = i;
			texts[i].addTextChangedListener(new TextWatcher() {

				@Override
				public void onTextChanged(CharSequence s, int start,
						int before, int count) {
					// TODO Auto-generated method stub

				}

				@Override
				public void beforeTextChanged(CharSequence s, int start,
						int count, int after) {
					// TODO Auto-generated method stub

				}

				@Override
				public void afterTextChanged(Editable s) {
					// TODO Auto-generated method stub
					int nextIndex = curIndex + 1;
					//当输入到最后一个EditText时关闭PopupWindow
					if (nextIndex >= texts.length) {
						dismiss();
						return;
					}
					texts[nextIndex].requestFocus();
				}
			});
		}

		btn_close = (ImageButton) view.findViewById(R.id.btn_close);
		btn_close.setOnClickListener(new View.OnClickListener() {

			public void onClick(View v) {
				// TODO Auto-generated method stub
				dismiss();
			}
		});

		this.setOnDismissListener(onDismissListener);

	}

	private OnDismissListener onDismissListener = new OnDismissListener() {

		public void onDismiss() {
			// TODO Auto-generated method stub
			if (onCompleteListener != null) {
				String[] text = new String[texts.length];
				for (int i = 0; i < texts.length; i++) {
					text[i] = texts[i].getText().toString();
				}
				onCompleteListener.onComplete(text);
			}
			// 清空&归位
			for (int i = 0; i < texts.length; i++) {
				texts[i].setText("");
			}
			texts[0].requestFocus();
		}

	};

	private OnCompleteListener onCompleteListener;

	public void setOnCompleteListener(OnCompleteListener onCompleteListener) {
		this.onCompleteListener = onCompleteListener;
	}

	public interface OnCompleteListener {
		public void onComplete(String[] texts);
	}

}

在Activity中的用法就简单了：

private PasswordPopupWindow popupWindow;

if (popupWindow == null) {
LayoutInflater mLayoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
View popup_view = mLayoutInflater.inflate(R.layout.popup_window_password,null);
popupWindow = new PasswordPopupWindow(context, popup_view);
//					popupWindow.setInputMethodMode(PopupWindow.INPUT_METHOD_FROM_FOCUSABLE);
					popupWindow.showAtLocation(container, Gravity.TOP, 0, 0);
					popupWindow.setOnCompleteListener(new PasswordPopupWindow.OnCompleteListener() {

								@Override
								public void onComplete(String[] texts) {
									// TODO Auto-generated method stub
									StringBuffer sb = new StringBuffer();
									for (int i = 0; i < texts.length; i++) {
										sb.append(texts[i]);
									}
									String p=sb.toString();
									if(p.length()==texts.length){
//doSomethingYouWant();
																		}
								}
							});
				} else {
					if (!popupWindow.isShowing()) {
						popupWindow.showAtLocation(container, Gravity.TOP, 0, 0);
					}
				}
				// 强制显示输入法
				toggleSoftInput(context);

如果弹出PasswordPopupWindow后没有弹出输入法，则强制显示输入法：

/**
	 * 如果输入法打开则关闭，如果没打开则打开
	 * 
	 * @param context
	 */
	protected void toggleSoftInput(Context context) {
		InputMethodManager inputMethodManager = (InputMethodManager) context
				.getSystemService(Context.INPUT_METHOD_SERVICE);
		inputMethodManager.toggleSoftInput(0,
				InputMethodManager.HIDE_NOT_ALWAYS);
	}

PasswordPopupWindow的布局文件popup_window_password.xml如下：

动画文件：

anim_top_in.xml

anim_top_out.xml

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