android:使用gallery和imageSwitch製作可左右迴圈滑動的圖片瀏覽器
阿新 • • 發佈:2018-12-23
為了使圖片瀏覽器左右無限迴圈滑動 我們要自定義gallery的adapter
如果要想自定義adapter首先要了解這幾個方法
@Override public int getCount() { // TODO Auto-generated method stub return 0; } @Override public Object getItem(int position) { // TODO Auto-generated method stub return null; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return 0; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub return null; }
其中getCount方法 是返回資料來源的數量
getItem方法 返回的是一個object物件 也就是返回目前容器中資料ID position所對應的物件
getItemId 返回目前容器中的資料ID
getView取得目前要顯示的View
如果要實現左右迴圈滑動 首先我們要返回資料來源的數量為最大值 然後把所有資料的ID對原本資料來源的數量取餘 最後設定gallery初始的位置在0-最大值的中間即可
更改後的adapter就是這樣
package com.example.imageswitcher; import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.Gallery; import android.widget.ImageView; import android.widget.ImageView.ScaleType; public class MyAdapter extends BaseAdapter{ private int id_image[]; private Context contex; public MyAdapter(Context contex,int id_image[]) { this.contex=contex; this.id_image=id_image; } @Override public int getCount() { // TODO Auto-generated method stub return Integer.MAX_VALUE; } @Override public Object getItem(int position) { // TODO Auto-generated method stub return id_image[position%id_image.length]; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position%id_image.length; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub ImageView imageView=new ImageView(contex); imageView.setBackgroundResource(id_image[position%id_image.length]); imageView.setLayoutParams(new Gallery.LayoutParams(250, 200)); imageView.setScaleType(ScaleType.FIT_XY); return imageView; } }
MainActivity
package com.example.imageswitcher; import android.os.Bundle; import android.app.Activity; import android.view.LayoutInflater.Factory; import android.view.Menu; import android.view.View; import android.view.Window; import android.view.animation.AnimationUtils; import android.widget.AdapterView; import android.widget.AdapterView.OnItemSelectedListener; import android.widget.Gallery; import android.widget.ImageSwitcher; import android.widget.ImageView; import android.widget.ImageView.ScaleType; import android.widget.ViewSwitcher.ViewFactory; public class MainActivity extends Activity implements OnItemSelectedListener,ViewFactory{ private ImageSwitcher imageSwitcher; private Gallery gallery; private int id_image[] = { R.drawable.beauty1, R.drawable.beauty2, R.drawable.beauty3, R.drawable.beauty4, R.drawable.beauty5, R.drawable.beauty6, R.drawable.beauty7, R.drawable.beauty8, R.drawable.beauty9}; private MyAdapter myAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_main); gallery = (Gallery) findViewById(R.id.id_gallery); imageSwitcher = (ImageSwitcher) findViewById(R.id.id_imageSwitcher); myAdapter=new MyAdapter(this, id_image); imageSwitcher.setFactory(this); gallery.setOnItemSelectedListener(this); //設定淡入淡出效果 imageSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); imageSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); gallery.setAdapter(myAdapter); //一定不要忘記 設定gallery的初始位置為中間即可 gallery.setSelection(id_image.length*100); } @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub imageSwitcher.setBackgroundResource(id_image[position%id_image.length]); } @Override public void onNothingSelected(AdapterView<?> parent) { // TODO Auto-generated method stub } @Override public View makeView() { // TODO Auto-generated method stub ImageView image=new ImageView(this); image.setScaleType(ScaleType.FIT_CENTER); return image; } }