1、文件放到如下路径下
mnt——sdcard——Pictures
2、3、可以观察到图库中增加了图片
因为我们读取图片的方式和图库读取图片的方式是相同的,图库中有图片意味着我们也能读取到图片
从Device File Exploer以下路径下导出数据库文件
data——data下的
查看image表会看到我们刚才导入的图片
Image类
public class Image {
private int id;
private String data;//path
private int size;
private String displayName;
private long dateTaken;
private int width;
private int height;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getData() {
return data;
}
public void setData(String data) {
this.data = data;
}
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
public String getDisplayName() {
return displayName;
}
public void setDisplayName(String displayName) {
this.displayName = displayName;
}
public long getDateTaken() {
return dateTaken;
}
public void setDateTaken(long dateTaken) {
this.dateTaken = dateTaken;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
}
IDao
public interface IDao<T> {
List<T> getData();
}
MusicDao
import android.content.ContentResolver;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.provider.MediaStore;
import android.util.Log;
import com.example.xx.myapplication2.entity.Image;
import java.util.ArrayList;
import java.util.List;
public class ImageDao implements IDao<Image>{
private Context context;
public ImageDao(Context context) {
this.context = context;
}
@Override
public List<Image> getData() {
//准备返回值
List<Image> images = new ArrayList<Image>();
//准备ContentResolver
ContentResolver cr = context.getContentResolver();
//准备Uri
Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
//执行查询,获取Cursor
//注意和数据库保持一致
String[] projection = {
"_id",//0
"_data",//1
"_size",//2
"_display_name",//3
"datetaken",//4
"width",//5
"height",//6
};
Cursor c = cr.query(uri, projection, null, null, null);
//遍历Cursor,读取数据,并封装到返回值
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
Image image = new Image();
image.setId(c.getInt(0));
image.setData(c.getString(1));
image.setSize(c.getInt(2));
image.setDisplayName(c.getString(3));
image.setDateTaken(c.getLong(4));
image.setWidth(c.getInt(5));
image.setHeight(c.getInt(6));
images.add(image);
}
//释放资源
c.close();
c = null;
//日志
for(Image image:images){
Log.d("Image","id:"+image.getId()+";data:"+image.getData()+";size:"+image.getSize()+
";displayname:"+image.getDisplayName()+";dataTaken:"+image.getDateTaken()+";width:"+image.getWidth()+
";height:"+image.getHeight());
}
//返回
return images;
}
}
万能的BaseAdapter
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.List;
public class BaseAdapter<T> extends android.widget.BaseAdapter {
private Context context;
private List<T> data;
private LayoutInflater inflater;
public BaseAdapter(Context context, List<T> data) {
setContext(context);
setData(data);
setInflater();
}
public Context getContext() {
return context;
}
public void setContext(Context context) {
if(context == null){
throw new IllegalArgumentException("参数Context不允许为null");
}
this.context = context;
}
public List<T> getData() {
return data;
}
public void setData(List<T> data) {
if(data == null){
data = new ArrayList<>();
}
this.data = data;
}
public LayoutInflater getInflater() {
return inflater;
}
public void setInflater() {
inflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int i) {
return null;
}
@Override
public long getItemId(int i) {
return 0;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
return view;
}
}
ImageAdapter
public class ImageAdapter extends BaseAdapter<Image> {
public ImageAdapter(Context context, List data) {
super(context, data);
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
ViewHolder viewHolder;
if(view == null){
viewHolder = new ViewHolder();
view = getInflater().inflate(R.layout.item_image,null);
viewHolder.imageView = (ImageView)view.findViewById(R.id.img_item);
view.setTag(viewHolder);
}else {
viewHolder = (ViewHolder) view.getTag();
}
Image image = getData().get(i);
Bitmap bitmap = BitmapFactory.decodeFile(image.getData());
viewHolder.imageView.setImageBitmap(bitmap);
return view;
}
class ViewHolder{
ImageView imageView;
}
}
MainActivity
public class MainActivity extends Activity implements View.OnClickListener {
private ListView listView;
private ImageAdapter imageAdapter;
private List<Image> imageList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = findViewById(R.id.lv_images);
imageList = new ImageDao(this).getData();
imageAdapter = new ImageAdapter(this,imageList);
listView.setAdapter(imageAdapter);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
default:
break;
}
}
}
activity_main
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".ui.MainActivity">
<ListView
android:id="@+id/lv_images"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
item_image
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
tools:context=".ui.MainActivity">
<ImageView
android:id="@+id/img_item"
android:layout_width="100dp"
android:layout_height="100dp" />
</LinearLayout>
AndroidManifest
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
手机打开相应权限
效果
如果想实现一行显示3个
可以把ListView控件改为GridView
<GridView
android:id="@+id/lv_images"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnWidth="90dp"
android:horizontalSpacing="9dp"
android:numColumns="3"
android:verticalSpacing="10dp"
/>