Android 当我的JSON中没有值时，我的应用程序崩溃
我正在发布“id”值（通过getintent传递给此活动） 到服务器并检索相应的JSONObjectAndroid 当我的JSON中没有值时，我的应用程序崩溃,android,Android,我正在发布“id”值（通过getintent传递给此活动） 到服务器并检索相应的JSONObject @Override protected Map<String, String> getParams() { Map<String, String> params = new HashMap<String, String>(); params.put("id", Uid);
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
@覆盖
受保护的映射getParams（）{
Map params=新的HashMap（）；
参数put（“id”，Uid）；
返回参数；
}
public class kill extends FragmentActivity {
GridView grid1;
CustomGrid_Album adapter;
private ProgressDialog pDialog;
String Uid,Disp;
public String category;
public String selected;
public static String imagename;
Button Alb_sel;
ArrayList<Item_album> gridArray = new ArrayList<Item_album>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.album_display);
grid1 = (GridView) findViewById(R.id.gridView2);
Uid = getIntent().getStringExtra("id");
Disp = getIntent().getStringExtra("disp");
Alb_sel=(Button)findViewById(R.id.album_to_select);
pDialog = new ProgressDialog(kill.this);
pDialog.setMessage("Loading...");
pDialog.show();
//fetching JSONArray
final RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
StringRequest stringRequest = new StringRequest(com.android.volley.Request.Method.POST, AppConfig.URL_Gallery4,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
} catch (JSONException e1) {
e1.printStackTrace();
}
int i=0;
for (i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
category = obj.getString("category_name");
selected = obj.getString("album_id");
imagename = obj.getString("org_image_name");
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
pDialog.dismiss();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "No images in this gallery", Toast.LENGTH_SHORT).show();
error.printStackTrace();
}
})
{
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
};
queue.add(stringRequest);
}
}
public类kill扩展了碎片活动{
GridView grid1；
自定义网格相册适配器；
私人对话；
字符串Uid，Disp；
公共字符串类别；
选择公共字符串；
公共静态字符串imagename；
按钮Alb_选择；
ArrayList gridArray=新的ArrayList（）；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.album_显示）；
grid1=（GridView）findViewById（R.id.gridView2）；
Uid=getIntent（）.getStringExtra（“id”）；
Disp=getIntent（）.getStringExtra（“Disp”）；
Alb_sel=（按钮）findviewbyd（R.id.album_to_select）；
pDialog=newprogressdialog（kill.this）；
设置消息（“加载…”）；
pDialog.show（）；
//获取JSONArray
final RequestQueue=Volley.newRequestQueue（getApplicationContext（））；
StringRequest StringRequest=新建StringRequest（com.android.volley.Request.Method.POST，AppConfig.URL\u Gallery4，
新的Response.Listener（）{
@凌驾
公共void onResponse（字符串响应）{
Datas.imageIds=新字符串[response.length（）]；
JSONArray arr=null；
试一试{
arr=新JSONArray（响应）；
}捕获（JSONException e1）{
e1.printStackTrace（）；
}
int i=0；
对于（i=0；iif(response.length()==0){
// error message
}else{
// your rest of the code
}
我只想在onResponse方法中添加两个检查：
...
public void onResponse(String response) {
// Check if the response itself is an empty string or null
if(TextUtils.isEmpty(response)) {
// Show your user feedback
return;
}
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
// Check if your JSON has no elements in it
if(arr.length == 0) {
// Show your user feedback
return;
}
} catch (JSONException e1) {
e1.printStackTrace();
}
...
您已声明
JSONArray arr=null
然后将服务器的JSON分配给该JSONArray
在获得该信息后添加一行
if(arr==null)
{
//toast
}
else
{
//whatever you want to do with JSON
}
StringRequest StringRequest=newstringrequest（com.android.volley.Request.Method.POST，AppConfig.URL\u Gallery4，
新的Response.Listener（）{
@凌驾
公共void onResponse（字符串响应）{
if（response.length（）==0）{
Toast.makeText（getActivity（），“找不到数据”，Toast.LENGTH_SHORT.show（）；
}
否则{
Datas.imageIds=新字符串[response.length（）]；
JSONArray arr=null；
试一试{
arr=新JSONArray（响应）；
}捕获（JSONException e1）{
e1.printStackTrace（）；
}
如果（阵列长度（）>0）{
int i=0；
对于（i=0；iif(arr==null)
{
//toast
}
else
{
//whatever you want to do with JSON
}
StringRequest stringRequest = new StringRequest(com.android.volley.Request.Method.POST, AppConfig.URL_Gallery4,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
if(response.length()==0){
Toast.makeText(getActivity(),"no data found",Toast.LENGTH_SHORT).show();
}
else{
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
} catch (JSONException e1) {
e1.printStackTrace();
}
if(arr.length()>0){
int i=0;
for (i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
category = obj.getString("category_name");
selected = obj.getString("album_id");
imagename = obj.getString("org_image_name");
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
}else{
Toast.makeText(getActivity(),"no data found",Toast.LENGTH_SHORT).show();
}
}
pDialog.dismiss();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "No images in this gallery", Toast.LENGTH_SHORT).show();
error.printStackTrace();
}
})
{
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
};
Datas.imageIds = new String[response.length()];
public void onResponse(String response) {
JSONArray arr = null;
try {
arr = new JSONArray(response);
Datas.imageIds = new String[arr.length()];
} catch (JSONException e1) {
e1.printStackTrace();
}
arr = new JSONArray(response);
if (arr.length() == 0) {
// TODO: Toast
}
if(response!=null){
try {
Datas.imageIds = new String[response.length()];
JSONArray arr = new JSONArray(response);
for (int i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
if(obj!=null){
if(obj.has("category_name") && !obj.isNull("category_name"){
category = obj.getString("category_name");
}
if(obj.has("album_id") && !obj.isNull("album_id"){
selected = obj.getString("album_id");
}
if(obj.has("org_image_name") && !obj.isNull("org_image_name"){
imagename = obj.getString("org_image_name");
}
if(obj.has("album_image") && !obj.isNull("album_image"){
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
pDialog.dismiss();
} catch (JSONException e1) {
e1.printStackTrace();
}
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "onErrorResponse: "+error.getMessage() );
}
})