Android ApiDemos/ScrollView2 添加自动滚动和智能焦点切换
2010-06-01 21:00
363 查看
Android ApiDemos/ScrollView2 添加自动滚动和智能焦点切换
首先总结一下andorid view的键盘事件处理过程:键盘事件首先交给当前Activity中获得焦点的View,该View的setKeyListener(OnKeyListener l)中设定的l的onKey方法被调用,若返回true,framwork不再处理,否则有framework继续处理.我就是用该方法实现的智能焦点切换。
然后是自动滚动的实现,当ViewGroup中添加了新的View后,不能马上进行滚动,因为此时相应的高度信息还没有更新,需要用Handler来向消息队列投递一个Runnale来进行滚动。
相关实现如下:
1.ScrollView2.java
package com.google.android.samples.view; import android.app.Activity; import android.os.Bundle; import android.os.Handler; import android.util.Log; import android.view.KeyEvent; import android.view.View; import android.widget.Button; import android.widget.LinearLayout; import android.widget.ScrollView; import android.widget.TextView; import com.google.android.samples.R; /** * Demonstrates wrapping a layout in a ScrollView. * */ public class ScrollView2 extends Activity { private static final String LOG_TAG = "ScrollView2"; private LinearLayout mLayout; private ScrollView mScrollView; private final Handler mHandler = new Handler(); @Override protected void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.scroll_view_2); mLayout = (LinearLayout) findViewById(R.id.layout); mScrollView = (ScrollView) findViewById(R.id.scrollview); Button button = (Button) findViewById(R.id.add_widget); button.setOnClickListener(mClickListener); //改变默认焦点切换 button.setKeyListener(mAddButtonKeyListener); } private Button.OnClickListener mClickListener = new Button.OnClickListener() { private int mIndex = 1; @Override public void onClick(View arg0) { // TODO Auto-generated method stub TextView textView = new TextView(ScrollView2.this); textView.setText("Text View " + mIndex); LinearLayout.LayoutParams p = new LinearLayout.LayoutParams( LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT ); mLayout.addView(textView, p); Button buttonView = new Button(ScrollView2.this); buttonView.setText("Button " + mIndex++); mLayout.addView(buttonView, p); //改变默认焦点切换 buttonView.setKeyListener(mNewButtonKeyListener); //投递一个消息进行滚动 mHandler.post(mScrollToBottom); } }; private Runnable mScrollToBottom = new Runnable() { @Override public void run() { // TODO Auto-generated method stub Log.d(LOG_TAG, "ScrollY: " + mScrollView.getScrollY()); int off = mLayout.getMeasuredHeight() - mScrollView.getHeight(); if (off > 0) { mScrollView.scrollTo(0, off); } } }; private View.OnKeyListener mNewButtonKeyListener = new View.OnKeyListener() { public boolean onKey(View v, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN && event.getAction() == KeyEvent.ACTION_DOWN && v == mLayout.getChildAt(mLayout.getChildCount() - 1)) { findViewById(R.id.add_widget).requestFocus(); return true; } return false; } }; private View.OnKeyListener mAddButtonKeyListener = new Button.OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { // TODO Auto-generated method stub Log.d(LOG_TAG, event.toString()); View viewToFoucus = null; if (event.getAction() == KeyEvent.ACTION_DOWN) { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_UP: int iCount = mLayout.getChildCount(); if ( iCount > 0) { viewToFoucus = mLayout.getChildAt(iCount - 1); } break; case KeyEvent.KEYCODE_DPAD_DOWN: if (mLayout.getChildCount() > 1) { viewToFoucus = mLayout.getChildAt(1); } break; default: break; } } if (viewToFoucus != null) { viewToFoucus.requestFocus(); return true; } else { return false; } } }; }
2.scroll_view_2.xml
<?xml version="1.0" encoding="utf-8"?> <!-- Demonstrates scrolling with a ScrollView. --> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <Button id="@+id/add_widget" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Add Widget"/> <ScrollView id="@+id/scrollview" android:layout_width="fill_parent" android:layout_height="wrap_content" android:scrollbars="vertical"> <LinearLayout id="@+id/layout" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content"> </LinearLayout> </ScrollView> </LinearLayout>
相关文章推荐
- Android添加自动滚动和智能焦点切换
- Android添加自动滚动和智能焦点切换1
- ScrollView2 添加自动滚动和智能焦点切换
- 关于android TextView在不需要较焦点的情况下,自动滚动文本实现小技巧
- android 图片滚动可以自动切换
- android--解决方案--自定义tabhost(动态添加选项+带自动水平滑动选项卡+手势切换选项卡及内容功能)
- Android中仿淘宝首页顶部滚动自定义HorizontalScrollView定时水平自动切换图片
- Android - 数据库自动更新,横竖屏切换,系统控件样式,Fragment添加到Activity,Fragment生命周期,缓存,获取/清除缓存
- android自定义Gallery实现手动和自动循环滚动切换图片
- 网易新闻首页的实现,可以添加,移除标签,自动滚动图片,无限左右切换图片
- jquery焦点图片切换(数字标注/手动/自动播放/横向滚动)
- android 如何实现水平方向根据焦点位置自动滚动?
- Android取消EditText默认自动获取焦点
- jquery图片滚动仿QQ商城带左右按钮控制焦点图片切换滚动
- android统一添加activity切换动画
- Android 控件之--发送邮件时的,收件人列表,可以自动匹配,可以删除,可以添加的。
- 高仿优酷Android客户端图片左右滑动(自动切换)
- 小笔记 使android界面打开时EditText不自动获得焦点
- android edittext 自动不获取焦点