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我从json文件读取数据到适配器，并在main.java下创建，当我尝试运行它时，它会显示任何内容。应用程序不会第一次运行，但当单击菜单中的项目时，它将运行
我试过菜单onclick下的相同代码，它的工作原理是，我希望它在应用第一次被毁掉时出现。
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
String url = "myjsonurl.php";
JSONArray jArray;
ProgressDialog dialog;
ListView mycustomlist = null;
WebView mywebview =null;
CustomAdapter myadapter = null;
ArrayList<news> mydatalist = new ArrayList<news>();
ArrayList<news> maşetData = new ArrayList<news>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myadapter = new CustomAdapter(this, mydatalist);
mycustomlist = (ListView)findViewById(R.id.listview);
mycustomlist.setAdapter(myadapter);
dialog = new ProgressDialog(this);
dialog.setMessage("Loading....");
dialog.show();
StringRequest request = new StringRequest(url, new Response.Listener<String>() {
@Override
public void onResponse(String string) {
parseJsonData(string);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError) {
Toast.makeText(getApplicationContext(), "Some error occurred!!", Toast.LENGTH_SHORT).show();
dialog.dismiss();
dialog.cancel();
}
});
RequestQueue rQueue = Volley.newRequestQueue(MainActivity.this);
rQueue.add(request);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
/* FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
*/
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
public void parseJsonData(final String jsonString) {
try {
jArray = new JSONArray(jsonString);
for(int i=0; i < jArray.length(); i++) {
JSONObject jObject = jArray.getJSONObject(i);
news news1 = new news();
news1.setTitle(jObject.getString("title"));
news1.setContent(Html.fromHtml(jObject.getString("content")));
news1.setDate(jObject.getString("date"));
news1.setImage("http://www.bolgegundem.com/d/news/" + jObject.getString("image").concat(".jpg"));
news1.setId(jObject.getString("id"));
news1.setCategory(jObject.getString("category"));
news1.set__comment_count(jObject.getString("__comment_count"));
news1.setHeadline(jObject.getString("headline"));
mydatalist.add(news1);
// http://www.bolgegundem.com/d/gallery/81_2.jpg
/* images.add("http://www.bolgegundem.com/d/gallery/" + id + "_" + imgUrl.replace(",", ".jpg"));*/
// al.add(title);
//imagelinks[i] = "http://www.bolgegundem.com/d/gallery/" + id + "_" + i + ".jpg";
}
// ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_activated_1, al);
//listview.setAdapter(adapter);
// listview.setBackgroundColor(rgb(0, 255, 255));
/* listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
if(i < links.length){
Uri uri = Uri.parse(links[i]);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}
});*/
if (dialog.isShowing()){
dialog.dismiss();
}
} catch (JSONException e) {
e.printStackTrace();
dialog.dismiss();
}
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.manşet) {
// Handle the camera action
} else if (id == R.id.Anasayfa) {
myadapter = new CustomAdapter(this, mydatalist);
mycustomlist = (ListView)findViewById(R.id.listview);
mycustomlist.setAdapter(myadapter);
} else if (id == R.id.ajansTv) {
} else if (id == R.id.foto) {
} else if (id == R.id.gundem) {
} else if (id == R.id.siyaset) {
}else if (id ==R.id.Ekonomi){
}else if (id ==R.id.spor){
}else if (id ==R.id.saglik){
}else if (id ==R.id.nav_share){
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
我的适配器类是这里
public class CustomAdapter extends BaseAdapter {
Context mycontext = null;
ArrayList<news> mydatalist;
public CustomAdapter(Context mycontext, ArrayList<news> mydatalist)
{
this.mycontext = mycontext;
this.mydatalist = mydatalist;
}
@Override
public int getCount() {
return this.mydatalist.size();
}
@Override
public Object getItem(int position) {
return this.mydatalist.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@SuppressLint("InflateParams")
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater myinflater = (LayoutInflater)mycontext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewHolder myholder = null;
if(convertView == null)
{
convertView = myinflater.inflate(R.layout.customlayout, null);
myholder = new ViewHolder();
myholder.mytextview1 = (TextView)convertView.findViewById(R.id.mytextview1);
myholder.mytextview2 = (TextView)convertView.findViewById(R.id.mytextview2);
myholder.mytextview3 = (TextView)convertView.findViewById(R.id.mytextview3);
myholder.myimageview1 = (ImageView)convertView.findViewById(R.id.imageView);
convertView.setTag(myholder);
}
else
{
myholder = (ViewHolder)convertView.getTag();
}
myholder.mytextview1.setText(mydatalist.get(position).getTitle());
myholder.mytextview2.setText(mydatalist.get(position).getContent());
myholder.mytextview3.setText(mydatalist.get(position).getDate());
myholder.myimageview1.setImageResource(R.drawable.bolgegundem);
new DownloadImageTask(myholder.myimageview1).execute(mydatalist.get(position).getImage());
return convertView;
}
static class ViewHolder
{
public TextView mytextview1;
public TextView mytextview2;
public TextView mytextview3;
public ImageView myimageview1;
}
private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
public DownloadImageTask(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
}
}
}
我该如何解决这个问题？
我尝试过，但它给出了错误。 –
我尝试过，但它给出了错误。 CustomAdapter中的customAdapter（Android.contex.contex ArrayList）无法应用于（Anonymous com.volley.Respond.Listener ，ArrayList ） –
将'this'更改为'MainActivity.this' –