小编yuv*_*a ツ的帖子

我想打开外部存储目录路径以编程方式保存文件.我试过但没有获得SD卡路径.我怎么能这样做？有什么解决方案吗？

private File path = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + "");

要么

private File path = new File(Environment.getExternalStorageDirectory() + "");

我尝试从两个方法上面获取路径,但两者都指向内部存储器.

当我们打开存储器时,如果sdcard没有,它将显示如下 -

设备存储和SD存储卡.

我想通过编码获得sd内存路径.我已经在清单中给予了许可 -

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

我收到以下错误:

> 02-06 23:10:24.104: E/dalvikvm(912): Could not find class
> 'android.support.v4.app.FragmentActivity', referenced from method
> com.robotium.solo.Waiter.getSupportFragment

当我运行一个项目时,我正在使用Coursera上的Android手持系统的移动应用程序编程.我相信这个错误与我的输出答案被认为是不正确有关.如果我可以修复此错误,我可以修复输出.

我最初运行测试时没有最新版本的Android支持存储库(未安装),但我现在根据SDK Manager(v4)拥有最新版本的Android支持存储库,甚至重新启动了Eclipse和模拟器,但我仍然得到错误.

如何根据SDK安装LogCat声明ASR不存在？

即使屏幕被锁定,如何在设备上启动活动.我尝试如下,但它不起作用.

广播接收器:

Intent alarmIntent = new Intent("android.intent.action.MAIN");
        alarmIntent.setClass(context, Alarm.class);
        alarmIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        alarmIntent.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED +
                             WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD +
                             WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON +
                             WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
        context.startActivity(alarmIntent);

在我的应用程序按钮单击我想改变imageview的大小.当我点击一个按钮我想增加5的视图尺寸(每个宽度和高度).点击其他按钮我想减小尺寸.i试过这个.我怎么能这样做？下面是code.its无法正常工作

 public void increase(View v)
{

    int height=imageView.getHeight();
    int width=imageView.getWidth();
    imageView.getLayoutParams().height = height+5;
    int h=imageView.getHeight();
    System.out.println("hhhhhhhhhh,,,,,,,,,,"+h);
    System.out.println("width n hight..."+width+"and"+height);


}

在我的自定义列表视图中,项目正在重复.项目的位置对于所有项目是相同的.代码如下

ListAdapter.java-

    public class ListAdapter extends BaseAdapter{

    private List<String> mName;
private List<Drawable> mIcon;
private Context mContext;

public ListAdapter(Context mContext, List<String> Name, List<Drawable> Icon) {
    this.mContext=mContext;
    this.mName=Name;
    this.mIcon=Icon;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return mName.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}

@Override
public View getView(final int position, View v, ViewGroup parent) { …

我想在地图视图中显示位置,地图大小应为200X200.我尝试在mapview中加载地图但是在点击方向指针2到3次显示正确的地图但没有移动之后它没有正确显示.

但是,当我使用完整大小的屏幕显示地图而不更改任何代码时,它正确加载.如何在小视图中显示相同的内容？

地图代码 -

static GoogleMap map;
private MapView mapView;
MapsInitializer.initialize(getApplicationContext());

        switch (GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext()) )
        {
        case ConnectionResult.SUCCESS:
            //Toast.makeText(getActivity(), "SUCCESS", Toast.LENGTH_SHORT).show();
            mapView = (MapView)findViewById(R.id.map);
            mapView.onCreate(savedInstanceState);
            // Gets to GoogleMap from the MapView and does initialization stuff
            if(mapView!=null)
            {
                map = mapView.getMap();
                map.getUiSettings().setMyLocationButtonEnabled(false);
                map.setMyLocationEnabled(true);
                CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(location, 10);
                map.animateCamera(cameraUpdate);
                map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            }
            break;
        case ConnectionResult.SERVICE_MISSING: 
            //Toast.makeText(getActivity(), "SERVICE MISSING", Toast.LENGTH_SHORT).show();
            break;
        case ConnectionResult.SERVICE_VERSION_UPDATE_REQUIRED: 
            //Toast.makeText(getActivity(), "UPDATE REQUIRED", Toast.LENGTH_SHORT).show();
            break;
        default: Toast.makeText(getApplicationContext(), GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext()), Toast.LENGTH_SHORT).show();
        }

        CameraPosition cameraPosition = new CameraPosition.Builder()
        .target(location).zoom(10).bearing(0) // Sets the orientation …

我正在尝试从android sqlite数据库中检索数据但是它的givine异常没有这样的列:

c=db.rawQuery("Select Name from stud Where Address="+a,null);

07-04 18:07:00.888: I/Database(648): sqlite returned: error code = 1, msg = no such column: aa
07-04 18:07:00.910: D/AndroidRuntime(648): Shutting down VM
07-04 18:07:00.910: W/dalvikvm(648): threadid=1: thread exiting with uncaught exception (group=0x40015560)
07-04 18:07:00.948: E/AndroidRuntime(648): FATAL EXCEPTION: main
07-04 18:07:00.948: E/AndroidRuntime(648): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.my.StudentInfoManagement/com.my.StudentInfoManagement.ListData}: android.database.sqlite.SQLiteException: no such column: aa: , while compiling: Select Name from stud Where Address=aa
07-04 18:07:00.948: E/AndroidRuntime(648):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) …

我已经创建了地图actvity.But它没有在mapview.just上显示地图显示空白块.有什么办法吗？

activity_main.xml-

 <?xml version="1.0" encoding="utf-8"?>
 <fragment xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/map"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:name="com.google.android.gms.maps.MapFragment"/>

活动代码 -

package com.example.googlemap;


import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}
}

清单文件 -

  <uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="16" />

<permission
    android:name="com.example.googlemap.permission.MAPS_RECEIVE"
    android:protectionLevel="signature" />

<meta-data
    android:name="com.google.android.maps.v2.AIzaSyDRv4Ul_9iPW-roHIsc8EuxKwkRN8jWivs"
    android:value="AIzaSyDRv4Ul_9iPW-roHIsc8EuxKwkRN8jWivs" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<!--
 The following two permissions are not required to use
 Google Maps Android API v2, but are recommended.
--> …

在我的应用程序中,我只使用列表视图来显示图像和文本.这是我的适配器编码

ArrayAdapter<String> adapter=new ArrayAdapter<String>(MainActivity.this, R.layout.list_item, R.id.name, arrList);

    listProductCategories.setAdapter(adapter);

    listProductCategories.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

              ImageView imgview = (ImageView) view.findViewById(R.id.iv_listitem);
                 //And change its background here
                 imgview.setBackgroundResource(R.drawable.fail);

            String name = ((TextView) view.findViewById(R.id.name))
                    .getText().toString();
            Toast.makeText(MainActivity.this, "" + name, 10).show();

        }
    });

这是上面编码的屏幕截图.

这里我突出显示所选列表项.但是我的输出显示了许多列表视图项目图像背景中的一些已更改..

请给我一个解决方案....

<ImageView android:id="@+id/iv_listitem" 
android:layout_width="20dp" 
android:layout_height="20dp" 
android:layout_gravity="center_vertical" 
android:background="@drawable/next_unselect"
android:focusable="false" /> 
<TextView
android:id="@+id/name" 
android:layout_width="match_parent"   
android:layout_height="wrap_content" 
android:layout_gravity="center_vertical"
android:focusable="false" 
android:text="TextView"
android:textColor="#003366" /> 

项目清单-

  <ImageView android:id="@+id/iv_listitem" android:layout_width="20dp" android:layout_height="20dp" android:layout_gravity="center_vertical" android:background="@drawable/next_unselect" android:focusable="false" />

  <TextView android:id="@+id/name" android:layout_width="match_parent" android:layout_height="wrap_content" …

如何在android中锁定或打开屏幕？我尝试在广播接收器中使用SCREEN_OFF和SCREEN_ON操作,但它无法正常工作.

public void onReceive(Context context, Intent intent) {
        Log.d("XYZ", "Screen ON/OFF");

        Toast.makeText(context, "screen",10000).show();
        if(intent.getAction().equals(Intent.ACTION_SCREEN_ON))
        {
.......
}
}

在活动中,我已注册广播,如 -

屏幕是我的广播接收器的对象

IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
            filter.addAction(Intent.ACTION_SCREEN_OFF);
            mContext.registerReceiver(screen, filter);