java - setImageResource 崩溃程序

Question

每当我尝试运行该行时，我的程序就会崩溃:

d1.setImageResource(R.drawable.clubs9);

我想不通为什么。它似乎与我使用类似代码行的另一个程序相同。我试过添加 getResources().getDrawable()，但它不会编译。我完全卡住了。任何帮助将不胜感激!

---

public class TCP extends Activity {
    private List<Card> cards;
    private ImageButton deal;
    private ImageButton fold;
    private ImageView d1;
    private ImageView d2;
    private ImageView d3;
    private ImageView p1;
    private ImageView p2;
    private ImageView p3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tcp);
        createDeck();
        d1.setImageResource(R.drawable.clubs9);
    }

---

XML

<ImageView
    android:id="@+id/d1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/p1"
    android:layout_alignTop="@+id/d2"
    android:src="@drawable/diamondsq" />

---

洛卡特:

08-04 12:11:49.154: E/AndroidRuntime(4709): FATAL EXCEPTION: main
08-04 12:11:49.154: E/AndroidRuntime(4709): java.lang.IllegalStateException: Could not execute method of the activity
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.view.View$1.onClick(View.java:3599)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.view.View.performClick(View.java:4204)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.view.View$PerformClick.run(View.java:17355)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.os.Handler.handleCallback(Handler.java:725)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.os.Handler.dispatchMessage(Handler.java:92)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.os.Looper.loop(Looper.java:137)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.app.ActivityThread.main(ActivityThread.java:5041)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at java.lang.reflect.Method.invokeNative(Native Method)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at java.lang.reflect.Method.invoke(Method.java:511)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at dalvik.system.NativeStart.main(Native Method)
08-04 12:11:49.154: E/AndroidRuntime(4709): Caused by: java.lang.reflect.InvocationTargetException
08-04 12:11:49.154: E/AndroidRuntime(4709):     at java.lang.reflect.Method.invokeNative(Native Method)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at java.lang.reflect.Method.invoke(Method.java:511)
08-04 12:11:49.154: E/AndroidRuntime(4709):     at android.view.View$1.onClick(View.java:3594)
08-04 12:11:49.154: E/AndroidRuntime(4709):     ... 11 more
08-04 12:11:49.154: E/AndroidRuntime(4709): Caused by: java.lang.NullPointerException
08-04 12:11:49.154: E/AndroidRuntime(4709):     at com.evorlor.threecardpoker.TCP.deal(TCP.java:64)
08-04 12:11:49.154: E/AndroidRuntime(4709):     ... 14 more

Answer 1

java.lang.NullPointerException because your d1 is null

所以用

d1=(ImageView)findViewById(R.id.d1);

所以你的代码应该是

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tcp);
        createDeck();
        d1=(ImageView)findViewById(R.id.d1);
        d1.setImageResource(R.drawable.clubs9);
    }