Question

我是Android新手，我正试图让我的应用程序从相机拍照。查看提供here的示例，我尝试在MainActivity.java中的应用程序中实现：

public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main); // line 17
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

static final int REQUEST_IMAGE_CAPTURE = 1;

public void dispatchTakePictureIntent(View view) {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
}
}

这是我的activity_main.xml：

    <RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView android:text="@string/welcome" android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:layout_centerHorizontal="true"
        android:textSize="40dp" android:textStyle="bold" android:textColor="#990000"/>
    <GridView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:numColumns="2"
        android:columnWidth="50dp"
        android:gravity="center_horizontal">
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/picture_1"
                android:onClick="dispatchTakePictureIntent"/>
        </GridView>

</RelativeLayout>

我收到以下错误：

java.lang.RuntimeException: Unable to start activity ComponentInfo{---/.MainActivity}: java.lang.UnsupportedOperationException: addView(View, LayoutParams) is not supported in AdapterView
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
        at android.app.ActivityThread.access$800(ActivityThread.java:139)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5102)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)
        Caused by: java.lang.UnsupportedOperationException: addView(View, LayoutParams) is not supported in AdapterView
        at android.widget.AdapterView.addView(AdapterView.java:478)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:759)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
          at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegaeBase.java:228)
        at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
        at ---/.MainActivity.onCreate(MainActivity.java:17)
        at android.app.Activity.performCreate(Activity.java:5248)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2173)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5102)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

我可能做错了什么，所以有人能指出我的错误吗？提前谢谢。

Answer 1

UnsupportedOperationException：addView（View，LayoutParams）不是 AdapterView支持

AdapterView的子类（在您的情况下为GRIDVIEW）无法在布局文件中手动添加子项或在代码中添加子项。

您的代码：

 <GridView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:numColumns="2"
        android:columnWidth="50dp"
        android:gravity="center_horizontal">
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/picture_1"
                android:onClick="dispatchTakePictureIntent"/>
        </GridView>

不要这样做！

因为这将调用GridView的addView方法，抛出异常。而是使用：

      <GridView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:numColumns="2"
            android:columnWidth="50dp"
            android:gravity="center_horizontal"/>

此外，如果在Activity的代码或适配器（其getView方法）中使用LayoutInflater.inflate方法，则不要将GridView作为第二个参数传递。例如，不要使用：

convertView  = inflator.inflate(R.layout.child, parent);

改为使用：

convertView  = inflator.inflate(R.layout.child, parent, false);

Answer 2

为什么要在yout xml中添加GridView中的Button？

GridView不是为此目的而设计的。将按钮放在GridView外面并尝试。错误与此有关。

GridView只能用于在网格图案中显示视图，它使用适配器显示数据。

Answer 3

使用您的网格视图如下：

 <GridView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:numColumns="2"
            android:columnWidth="50dp"
            android:gravity="center_horizontal"/>

GridView用于在网格模式中显示视图，同样使用Adapter来显示数据。

Android - 用相机拍照

3 个答案: