[Android] 通过GridView仿微信动态添加本地图片示例代码

前面文章讲述的都是"随手拍"中图像处理的操作,此篇文章主要讲述GridView控件实现添加本地图片并显示.主要是关于GridView控件的基本操作,通常可以通过自定义继承BaseAdapter的适配器加载图片,而下面讲述的不是自定义的适配器,而是调用SimpleAdapter实现的.至于上传发布与网络交互此处不讲述,后面文章会讲!

一. 实现效果

主要是通过点击+从本地相册中添加图片,同时显示图片至GridView.点击图片可以进行删除操作,同时界面中的发布EditView控件也很好看,不足之处在于+好没有移动至最后,但原理相同.

    

二. 项目工程结构

三. 界面布局详细代码

1.主界面activity_main.xml

主要通过相对布局实现,第一部分是底部的TextView,中间是EditView和GridView相对布局,下面是两个按钮.同时EditView调用res/drawable-hdpi中的editview_shape.xml,GridView显示的每张图片通过griditem_addpic.xml实现.

<RelativeLayout xmlns:Android="Http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:id="@+id/container" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  tools:context="com.example.suishoupaipublish.MainActivity" 
  tools:ignore="MergeRootFrame" > 
  <!-- 顶部添加文字 -->  
  <RelativeLayout  
    android:id="@+id/Layout_top"  
    android:orientation="horizontal"   
    android:layout_width="fill_parent"  
    android:layout_height="40dp"  
    android:layout_marginTop="5dp" 
    android:layout_alignParentTop="true"  
    android:gravity="center">  
    <TextView  
      android:layout_width="fill_parent"   
      android:layout_height="wrap_content"   
      android:textSize="25sp" 
      android:gravity="center" 
      android:text="发布信息" />  
  </RelativeLayout>  
  <!-- 底部按钮 -->  
  <RelativeLayout  
    android:id="@+id/Layout_bottom"   
    android:layout_alignParentBottom="true" 
    android:layout_width="fill_parent"   
    android:layout_height="50dp" 
    android:gravity="center" >  
    <Button  
      android:id="@+id/button1"  
      android:layout_width="wrap_content"  
      android:layout_height="fill_parent" 
      android:textSize="20sp" 
      android:text="发布拍拍" />  
    <Button  
      android:id="@+id/button2"  
      android:layout_width="wrap_content"  
      android:layout_height="fill_parent" 
      android:layout_toRightOf="@+id/button1" 
      android:textSize="20sp" 
      android:text="取消发布" /> 
  </RelativeLayout>  
  <!-- 显示图片 -->  
  <RelativeLayout  
    android:id="@+id/Content_Layout"    
    android:layout_width="fill_parent"   
    android:layout_height="fill_parent"  
    android:layout_above="@id/Layout_bottom"   
    android:layout_below="@id/Layout_top"   
    android:gravity="center">    
    <LinearLayout   
      android:layout_width="match_parent"  
      android:layout_height="match_parent"  
      android:orientation="vertical" 
      android:layout_alignParentBottom="true" >  
      <!-- 设置运行多行 设置圆角图形 黑色字体--> 
      <EditText  
        android:id="@+id/editText1" 
        android:layout_height="120dp" 
        android:layout_width="fill_parent" 
        android:textColor="#000000" 
        android:layout_margin="12dp" 
        android:textSize="20sp" 
        android:hint="随手说出你此刻的心声..." 
        android:maxLength="500" 
        android:singleLine="false" 
        android:background="@drawable/editview_shape" /> 
      <!-- 网格显示图片 行列间距5dp 每列宽度90dp --> 
      <GridView 
        android:id="@+id/gridView1" 
        android:layout_width="fill_parent" 
        android:layout_height="200dp" 
        android:layout_margin="10dp" 
        android:background="#EFDFDF" 
        android:horizontalSpacing="5dp" 
        android:verticalSpacing="5dp" 
        android:numColumns="4" 
        android:columnWidth="90dp" 
        android:stretchMode="columnWidth" 
        android:gravity="center" > 
      </GridView> 
      <TextView  
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="(友情提示:只能添加9张图片,长按图片可以删除已添加图片)" 
        android:gravity="center" /> 
    </LinearLayout> 
  </RelativeLayout> 
</RelativeLayout> 

2.显示ImageView图片布局griditem_addpic.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:gravity="center" 
  android:descendantFocusability="blocksDescendants" 
  android:orientation="vertical" > 
  <RelativeLayout 
    android:layout_gravity="center" 
    android:layout_width="80dp" 
    android:layout_height="80dp" 
    android:orientation="vertical" > 
    <ImageView 
      android:layout_marginTop="10dp" 
      android:layout_marginRight="10dp" 
      android:id="@+id/imageView1" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent" 
      android:scaleType="fitXY" 
      android:src="@drawable/gridview_addpic" /> 
  </RelativeLayout> 
</LinearLayout> 

3.设置EditView控件圆角和颜色 editview_shape.xml

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"  
  android:shape="rectangle"  
  android:padding="10dp"> 
  <!-- 填充editView的颜色 --> 
  <soild android:color="#ffffff"/> 
  <!-- 设置圆角的弧度，radius半径越大，editView的边角越圆 --> 
  <corners  
    android:radius="15dp" 
    android:bottomRightRadius="15dp" 
    android:bottomLeftRadius="15dp" 
    android:topLeftRadius="15dp"  
    android:topRightRadius="15dp"/> 
  <stroke 
    android:color="#32CD32"  
    android:width="4px" />  
</shape> 

四. 代码详解

它主要是思想如下:

1.通过SimpleAdapter适配器实现实现加载图片,在gridView1.setOnItemClickListener()点击函数中响应不同操作.

2.当点击加号图片(+)时,调用本地相册通过Intent实现获取图片路径存于字符串pathImage.

3.获取图片路径后在onResume中刷新图片,通过GridView的setAdapter()和notifyDataSetChanged()()函数刷新加载图片.

4.点击图片时会获取其position,通过dialog()函数弹出对话框提示是否删除,通过remove实现删除.

具体代码如下所示：

public class MainActivity extends Activity { 
  private GridView gridView1;       //网格显示缩略图 
  private Button buttonPublish;      //发布按钮 
  private final int IMAGE_OPEN = 1;    //打开图片标记 
  private String pathImage;        //选择图片路径 
  private Bitmap bmp;           //导入临时图片 
  private ArrayList<HashMap<String, Object>> imageItem; 
  private SimpleAdapter simpleAdapter;   //适配器 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
     
    getWindow().setSoftInputMode(WindowManager.LayoutParams. 
        SOFT_INPUT_ADJUST_PAN); 
    //锁定屏幕 
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); 
    setContentView(R.layout.activity_main); 
    //获取控件对象 
    gridView1 = (GridView) findViewById(R.id.gridView1); 
     
    //获取资源图片加号 
    bmp = BitmapFactory.decodeResource(getResources(), R.drawable.gridview_addpic); 
    imageItem = new ArrayList<HashMap<String, Object>>(); 
    HashMap<String, Object> map = new HashMap<String, Object>(); 
    map.put("itemImage", bmp); 
    imageItem.add(map); 
    simpleAdapter = new SimpleAdapter(this,  
        imageItem, R.layout.griditem_addpic,  
        new String[] { "itemImage"}, new int[] { R.id.imageView1});  
     
    simpleAdapter.setViewBinder(new ViewBinder() {  
      @Override  
      public boolean setViewValue(View view, Object data,  
          String textRepresentation) {  
        // TODO Auto-generated method stub  
        if(view instanceof ImageView && data instanceof Bitmap){  
          ImageView i = (ImageView)view;  
          i.setImageBitmap((Bitmap) data);  
          return true;  
        }  
        return false;  
      } 
    });  
    gridView1.setAdapter(simpleAdapter); 
     
    gridView1.setOnItemClickListener(new OnItemClickListener() { 
      @Override 
      public void onItemClick(AdapterView<?> parent, View v, int position, long id) 
      { 
        if( imageItem.size() == 10) { //第一张为默认图片 
          Toast.makeText(MainActivity.this, "图片数9张已满", Toast.LENGTH_SHORT).show(); 
        } 
        else if(position == 0) { //点击图片位置为+ 0对应0张图片 
          Toast.makeText(MainActivity.this, "添加图片", Toast.LENGTH_SHORT).show(); 
          //选择图片 
          Intent intent = new Intent(Intent.ACTION_PICK,     
              android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);  
          startActivityForResult(intent, IMAGE_OPEN);  
          //通过onResume()刷新数据 
        } 
        else { 
          dialog(position); 
          //Toast.makeText(MainActivity.this, "点击第"+(position + 1)+" 号图片",  
          //   Toast.LENGTH_SHORT).show(); 
        } 
      } 
    });  
  } 
  //获取图片路径 响应startActivityForResult  
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
    super.onActivityResult(requestCode, resultCode, data);     
    //打开图片  
    if(resultCode==RESULT_OK && requestCode==IMAGE_OPEN) {     
      Uri uri = data.getData();  
      if (!TextUtils.isEmpty(uri.getAuthority())) {  
        //查询选择图片  
        Cursor cursor = getContentResolver().query(  
            uri,  
            new String[] { MediaStore.Images.Media.DATA },  
            null,   
            null,   
            null);  
        //返回 没找到选择图片  
        if (null == cursor) {  
          return;  
        }  
        //光标移动至开头 获取图片路径  
        cursor.moveToFirst();  
        pathImage = cursor.getString(cursor  
            .getColumnIndex(MediaStore.Images.Media.DATA));  
      } 
    } //end if 打开图片 
  } 
  //刷新图片 
  @Override 
  protected void onResume() { 
    super.onResume(); 
    if(!TextUtils.isEmpty(pathImage)){ 
      Bitmap addbmp=BitmapFactory.decodeFile(pathImage); 
      HashMap<String, Object> map = new HashMap<String, Object>(); 
      map.put("itemImage", addbmp); 
      imageItem.add(map); 
      simpleAdapter = new SimpleAdapter(this,  
          imageItem, R.layout.griditem_addpic,  
          new String[] { "itemImage"}, new int[] { R.id.imageView1});  
      simpleAdapter.setViewBinder(new ViewBinder() {  
        @Override  
        public boolean setViewValue(View view, Object data,  
            String textRepresentation) {  
          // TODO Auto-generated method stub  
          if(view instanceof ImageView && data instanceof Bitmap){  
            ImageView i = (ImageView)view;  
            i.setImageBitmap((Bitmap) data);  
            return true;  
          }  
          return false;  
        } 
      });  
      gridView1.setAdapter(simpleAdapter); 
      simpleAdapter.notifyDataSetChanged(); 
      //刷新后释放防止手机休眠后自动添加 
      pathImage = null; 
    } 
  } 
   
  protected void dialog(final int position) { 
    AlertDialog.Builder builder = new Builder(MainActivity.this); 
    builder.setMessage("确认移除已添加图片吗？"); 
    builder.setTitle("提示"); 
    builder.setPositiveButton("确认", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int which) { 
        dialog.dismiss(); 
        imageItem.remove(position); 
        simpleAdapter.notifyDataSetChanged(); 
      } 
    }); 
    builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int which) { 
        dialog.dismiss(); 
        } 
      }); 
    builder.create().show(); 
  } 
} 

同时需要在AndroidMainfest.xml中添加权限操作SD卡和网络上传至服务器.

<!-- 申明网络权限 --> 
<uses-permission android:name="android.permission.INTERNET" /> 
<!-- 申明权限 操作SD卡 -->  
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 

五. 总结

该文章需要注意一个地方：在使用SimpleAdapter适配器加载bmp图片时,可能在GridView中不显示.即HashMap中map.put("itemImage",bmp)不显示图片,而使用put装入R.drawable.img却能显示.

这时有两种解决方法,一种是自定义继承BaseAdapter的适配器实现;另一种方法则是如上所示通过ViewBinder()接口实现,感谢博主dmin_提供的方法.

demo下载地址：http://xiazai.jb51.net/201701/yuanma/GirdViewTest_jb51.rar

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