android 小方法

小方法

1.获取屏幕分辨率：

public class BaseTools {

    public static int getWindowWidth(Context context) {
        // 获取屏幕分辨率
        WindowManager wm = (WindowManager) (context
                .getSystemService(Context.WINDOW_SERVICE));
        DisplayMetrics dm = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(dm);
        int mScreenWidth = dm.widthPixels;
        return mScreenWidth;
    }

    public static int getWindowHeigh(Context context) {
        // 获取屏幕分辨率
        WindowManager wm = (WindowManager) (context
                .getSystemService(Context.WINDOW_SERVICE));
        DisplayMetrics dm = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(dm);
        int mScreenHeigh = dm.heightPixels;
        return mScreenHeigh;
    }
}

2.android:用getIdentifier()获取资源Id

项目中一问题，从获取图片名称后，然后调用图片。直接用R.drawable.?无法调用。解决：

主要由两种方法，个人建议第二种。 
1). 不把图片放在res/drawable下，而是存放在src某个package中（如：com.drawable.resource），这种情况下的调用方法为： 

String path = "com/drawable/resource/imageName.png"; 
InputStream is = getClassLoader().getResourceAsStream(path); 
Drawable.createFromStream(is, "src"); 

2). 如果还是希望直接使用res/drawable中的图片，就需要通过下面的方法了： 
假设创建工程的时候，填写的package名字为：com.test.image 

int resID = getResources().getIdentifier("imageName", "drawable", "com.test.image"); 
Drawable image = getResources().getDrawable(resID);

 3.动态获取id的方法二之反射

Field field = R.drawable.class.getField(type);
int i = field.getint(new R.drawable());  //获取R.drawable换称呼null

例子:

for(int i = 0; i < 107; i++){
            try {
                if(i<10){
                    Field field = R.drawable.class.getDeclaredField("f00" + i);
                    int resourceId = Integer.parseInt(field.get(null).toString());
                    imageIds[i] = resourceId;
                }else if(i<100){
                    Field field = R.drawable.class.getDeclaredField("f0" + i);
                    int resourceId = Integer.parseInt(field.get(null).toString());
                    imageIds[i] = resourceId;
                }else{
                    Field field = R.drawable.class.getDeclaredField("f" + i);
                    int resourceId = Integer.parseInt(field.get(null).toString());
                    imageIds[i] = resourceId;
                }
            } catch (NumberFormatException e) {
                e.printStackTrace();
            } catch (SecurityException e) {
                e.printStackTrace();
            } catch (IllegalArgumentException e) {
                e.printStackTrace();
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
            Map<String,Object> listItem = new HashMap<String,Object>();
            listItem.put("image", imageIds[i]);
            listItems.add(listItem);
        }

 4.再按一次退出系统：

long waitTime = 2000;  
long touchTime = 0;  
  
@Override  
public boolean onKeyDown(int keyCode, KeyEvent event) {  
    if(event.getAction() == KeyEvent.ACTION_DOWN && KeyEvent.KEYCODE_BACK == keyCode) {  
        long currentTime = System.currentTimeMillis();  
        if((currentTime-touchTime)>=waitTime) {  
            Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();  
            touchTime = currentTime;  
        }else {  
            finish();  
        }  
        return true;  
    }  
    return super.onKeyDown(keyCode, event);  
}  

 5.在Action_Move事件中滑动的时候禁止Action_Down事件：

MotionEvent cancelEvent = MotionEvent.obtain(event);
            cancelEvent
                    .setAction(MotionEvent.ACTION_CANCEL
                            | (event.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));
            onTouchEvent(cancelEvent);

 6.在listView中tem 内如果有button等控件时，在监听listview的onitemclick事件时，焦点会被item内的button、imagebutton等控 件抢走，从而导致在listview设置了onitemclick事件后不会被触发。

解决方法是在初始化item的时候屏蔽掉其内部button等控件的 焦点获取，具体方法可以在自定义item的根控件中调用：

 

setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);   

 7.在ListView中的使用addHeadView(View view)的时候，如果添加的View是ViewPager的话，ViewPager的左右滑动事件会和ListView滑动事件相冲突，这里就涉及到事件分发的原理了，下面给出一点解决这个问题的代码：

　　1)自定义一个ListView结合GestureDetector，再在自定义ListView的事件拦截函数onInterceptTouchEvent(MotionEvent ev)，的返回值进行拦截

　　

public class MyListView extends ListView {

    private GestureDetector mGestureDetector;

    private OnTouchListener mGestureListener;

    private ViewPager viewPager;

    private Context context;

    public MyListView(Context context) {
        super(context);
        this.context = context;
    }

    public void setViewPager(ViewPager viewPager) {
        this.viewPager = viewPager;
    }

    public MyListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        mGestureDetector = new GestureDetector(new YScrollDetector());
        setFadingEdgeLength(0);

    }

    public MyListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        super.onInterceptTouchEvent(ev);
        return mGestureDetector.onTouchEvent(ev);
    }

    private class YScrollDetector extends SimpleOnGestureListener {
        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2,
                float distanceX, float distanceY) {
            if (Math.abs(distanceY) >= Math.abs(distanceX)) {
                System.out.println("主要是上下滑动");
                return true;
            }
            return false;
        }

        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            Toast.makeText(context, "图" + viewPager.getCurrentItem(), 1).show();
            return super.onSingleTapUp(e);
        }
    }

}

 8.查看root后的手机的，所连接的wifi密码：

 

 9.my note lianghardstudy@163.com  d*********