Question

我想将 JSONArray 转换为 String [] 。
在我的代码中没有错误，但是当我在logcat中编译时错误引用了行：

detail[i] =
            "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
            "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
            "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
            "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
            "--------------------------------";

detail[]为String[]，info_p为JSONArray
这是我的完整代码包含错误编译：

public class InfoPelanggaranActivity extends Activity{
private static final String TAG = InfoPelanggaranActivity.class.getCanonicalName();
public static JSONArray info_p;//delegated isi response
ListView _lv_detail;
Button _btn_gotoAdd;
String[] detail;
int arrayLength;
ArrayList<String> detailList;
ArrayAdapter<String> listAdapter;

public void onCreate(Bundle savedIntanceState){
    super.onCreate(savedIntanceState);
    Log.v(TAG, "Start onCreate InfoPelanggaranActivity");
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_infopelanggaran);

    _lv_detail = (ListView) findViewById(R.id.lv_detail);
    _btn_gotoAdd = (Button) findViewById(R.id.btn_gotoAdd);
    _btn_gotoAdd.setOnClickListener(new ClickKeAdd());
    setDetails();
}

private String[] setDetails() {
    // TODO Auto-generated method stub
    arrayLength = info_p.length();
    for(int i = 0; i<arrayLength; i++){
        Log.v(TAG, "Start setDetails(), for Index: "+i);
        JSONObject jsonMain = info_p.optJSONObject(i);
        detail[i] = new String[]{
                "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
                "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
                "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
                "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
                "--------------------------------"};                    
    }
    Log.w(TAG, "detail[i]: "+detail.length);
    detailList = new ArrayList<String>();
    detailList.addAll(Arrays.asList(detail));
    //
    listAdapter = new ArrayAdapter<String>(this,R.layout.row_infopelanggaran,detailList);
    _lv_detail.setAdapter(listAdapter);     
    return detail;
}
public class ClickKeAdd implements View.OnClickListener{

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Intent i = new Intent(InfoPelanggaranActivity.this,AddPelanggaranActivity.class);
        startActivity(i);           
    }

}

}

这是 EXCEPTION ：

09-30 18:41:58.226: E/AndroidRuntime(3711): FATAL EXCEPTION: main
09-30 18:41:58.226: E/AndroidRuntime(3711): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.peti/com.peti.InfoPelanggaranActivity}: java.lang.NullPointerException
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.os.Looper.loop(Looper.java:137)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread.main(ActivityThread.java:5041)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at java.lang.reflect.Method.invokeNative(Native Method)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at java.lang.reflect.Method.invoke(Method.java:511)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at dalvik.system.NativeStart.main(Native Method)
09-30 18:41:58.226: E/AndroidRuntime(3711): Caused by: java.lang.NullPointerException
09-30 18:41:58.226: E/AndroidRuntime(3711):     at com.peti.InfoPelanggaranActivity.setDetails(InfoPelanggaranActivity.java:54)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at com.peti.InfoPelanggaranActivity.onCreate(InfoPelanggaranActivity.java:40)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.Activity.performCreate(Activity.java:5104)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
09-30 18:41:58.226: E/AndroidRuntime(3711):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
09-30 18:41:58.226: E/AndroidRuntime(3711):     ... 11 more

为什么会这样？为什么我不能填写详细信息[]？
请有人帮帮我..

Answer 1

好吧得到了......

detail[i] = new String[]{
                "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
                "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
                "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
                "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
                "--------------------------------"};

这是你的第54行

这里你使用大小为1的new运算符创建String Array，因为没有逗号分隔符即

new String[]{
            "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
            "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
            "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
            "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
            "--------------------------------"};

并尝试将其分配到名为 detail [i] 的字符串中这种类型的转换无法自动完成。

现在，解决方案是... arrayLength = info_p.length(); 添加detail=new String[arrayLength]

和内部循环更改

detail[i] = new String[]{
            "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
            "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
            "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
            "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
            "--------------------------------"};

到

detail[i] = "NAMA SIM       : "+jsonMain.optString("nama_pengendara").toString()+"\n"+
            "IDENTITAS      : "+jsonMain.optString("jenis_identitas").toString()+"\n"+
            "NO.IDENTITAS   : "+jsonMain.optString("no_identitas").toString()+"\n"+
            "PELANGGARAN    : "+jsonMain.optString("jenis_pelanggaran").toString()+"\n"+
            "--------------------------------";

将JSONArray解析为JSONObject并将String转换为String []

1 个答案: