1.实现代码如下：
public class MainActivity extends Activity {private int[] mImages = { R.drawable.juxie, R.drawable.mojie,R.drawable.sheshou, R.drawable.shizi, R.drawable.shuangyu,R.drawable.shuangzi, R.drawable.shuiping, R.drawable.tiancheng,R.drawable.tianxie };private String[] mImageNames = { "巨蟹座", "摩羯座", "射手座", "狮子座", "双鱼座", "双子座","水平座", "天秤座", "天蝎座" };private int mCurrentImage = 0;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);DisplayMetrics metric = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(metric);final int width = metric.widthPixels;final ImageView imgView = (ImageView) findViewById(R.id.image);final EditText edit = (EditText) findViewById(R.id.edt);imgView.setImageResource(mImages[0]);edit.setText(mImageNames[0]);imgView.setOnTouchListener(new OnTouchListener() {@Overridepublic boolean onTouch(View v, MotionEvent event) {if (event.getAction() == MotionEvent.ACTION_DOWN) {if (event.getX() < width / 2) {if (mCurrentImage == 0) {mCurrentImage = mImages.length - 1;} else {mCurrentImage--;}} else {if (mCurrentImage == mImages.length - 1) {mCurrentImage = 0;} else {mCurrentImage++;}}}imgView.setImageResource(mImages[mCurrentImage]);edit.setText(mImageNames[mCurrentImage]);return true;}});}}
2.实现效果
3.该程序用到了获取屏幕大小的方法：
DisplayMetrics metric = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(metric);final int width = metric.widthPixels;
为什么要获取pixel而不是dip呢，这是因为我查看了API后得出的结果，在onTouch（）方法中通过event.getX();返回的正是pix。API中是这样说的：
getXpublic final float getX()Returns the X coordinate of this event. <span style="color:#ff0000;">Whole numbers are pixels;</span> the value may have a fraction for input devices that are sub-pixel precise.
4.给出px和dip的转换：
public static int dip2px(Context context, float dipValue) {float scale = context.getResources().getDisplayMetrics().density;return (int) (dipValue * scale + 0.5f);}public static int px2dip(Context context, float pxValue) {float scale = context.getResources().getDisplayMetrics().density;return (int) (pxValue / scale + 0.5f);}
希望以后可以用上这个转换
