问题
I am working on a project where i have a URL in JSONObjects and i have to show those items in a listview with the course names being the items. When the user clicks a course name in the list, a new activity must open with the grades and the coefficient available there in a similar listview. (those informations are available at http://benitobertoli.com/grades.html ) I wrote a code but i got stuck when it arrived to send data from the first activity to the other via parcelable.. can anyone PLEASE help me and show me how to do it ?
This is my code:
public class MainActivityJSON extends ListActivity
{
protected String[] mBlogPostTitles;
public static final String TAG = MainActivityJSON.class.getSimpleName();
protected JSONObject mBlogData;
protected ProgressBar mProgressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity_json);
mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
mProgressBar.setVisibility(View.VISIBLE);
if(isNetworkAvailable())
{
GetBlogPostsTask getBlogPostsTask = new GetBlogPostsTask();
getBlogPostsTask.execute();
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("ERROR !!");
builder.setMessage("Sorry there was an error getting data from the Internet.\nNetwork Unavailable!");
builder.setPositiveButton(android.R.string.ok, null);
AlertDialog dialog = builder.create();
dialog.show();
Toast.makeText(this, "Network Unavailable!", Toast.LENGTH_LONG).show();
}
}
private boolean isNetworkAvailable()
{
ConnectivityManager manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if(networkInfo != null && networkInfo.isConnected())
{
isAvailable = true;
return isAvailable;
}
else
return isAvailable;
}
@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_activity_json, menu);
return true;
}
private class GetBlogPostsTask extends AsyncTask<Object, Void, JSONObject>
{
@Override
protected JSONObject doInBackground(Object... arg0)
{
int responseCode = -1;
JSONObject jsonResponse = null;
try
{
URL blogFeedUrl = new URL("http://benitobertoli.com/grades.html");
HttpURLConnection connection = (HttpURLConnection) blogFeedUrl.openConnection();
connection.connect();
responseCode = connection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK)
{
InputStream inputStream = connection.getInputStream();
Reader reader = new InputStreamReader(inputStream);
int contentLength = connection.getContentLength();
char[] charArray = new char[contentLength];
reader.read(charArray);
String responseData = new String(charArray);
jsonResponse = new JSONObject(responseData);
}
else
{
Log.i(TAG, "Unsuccessfull Http Response Code: " + responseCode);
}
}catch (MalformedURLException e) { Log.e(TAG, "Exception caught ", e);
}catch (IOException e) { Log.e(TAG, "Exception caught ", e);
}catch (Exception e) { Log.e(TAG, "Exception caught ", e);
}
return jsonResponse;
}
@Override
protected void onPostExecute(JSONObject result)
{
mBlogData = result;
updateList();
}
}
@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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void updateList()
{
mProgressBar.setVisibility(View.INVISIBLE);
if(mBlogData == null)
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("ERROR !!");
builder.setMessage("Sorry there was an error getting data from the Internet");
builder.setPositiveButton(android.R.string.ok, null);
AlertDialog dialog = builder.create();
dialog.show();
TextView emptyTextView = (TextView) getListView().getEmptyView();
emptyTextView.setText(getString(R.string.no_items));
}
else {
try {
JSONArray jsonPosts = mBlogData.getJSONArray("data");
mBlogPostTitles = new String[jsonPosts.length()];
//ArrayList<HashMap<String, String>> blogPosts = new ArrayList<HashMap<String, String>>();
for(int i =0 ; i < jsonPosts.length() ; i++)
{
JSONObject post = jsonPosts.getJSONObject(i);
String course = post.getString("course");
course = Html.fromHtml(course).toString();
//String coet = post.getString("coet");
//coet = Html.fromHtml(coet).toString();
//HashMap<String, String> blogPost = new HashMap<String, String>();
//blogPost.put("course", course);
//blogPost.put("coet", "coefficient: "+coet);
//blogPosts.add(blogPost);
mBlogPostTitles[i] = course;
}
//String[] keys = { "course","coet" };
//int[] ids = { android.R.id.text1 , android.R.id.text2 };
//SimpleAdapter adapter = new SimpleAdapter(this, blogPosts, android.R.layout.simple_list_item_2, keys, ids);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,
mBlogPostTitles);
setListAdapter(adapter);
} catch (JSONException e) {
Log.e(TAG, "Exception caught", e);
}
}
}
public void PacelableMethod()
{
Send mSend = new Send();
Intent mIntent = new Intent(this, DetailsJSON.class);
Bundle mBundle = new Bundle();
mBundle.putParcelable(key, mSend);
mIntent.putExtras(mBundle);
startActivity(mIntent);
}
public class Send implements Parcelable
{
private String trim1;
private String trim2;
private String trim3;
private String finalgrade;
public String getTrim1() {
return trim1;
}
public void setTrim1(String Trim1) {
this.trim1 = Trim1;
}
public String getTrim2() {
return trim2;
}
public void setTrim2(String Trim2) {
this.trim2 = Trim2;
}
public String getPublishTime() {
return trim3;
}
public void setPublishTime(String Trim3) {
this.trim3 = Trim3;
}
public String getFinalgrade() {
return finalgrade;
}
public void setFinalgrade(String finalgrade) {
this.finalgrade = finalgrade;
}
public final Parcelable.Creator<Send> CREATOR = new Creator<Send>()
{
public Send createFromParcel(Parcel source)
{
Send mBook = new Send();
mBook.trim1 = source.readString();
mBook.trim2 = source.readString();
mBook.trim3 = source.readString();
return mBook;
}
public Send[] newArray(int size)
{
return new Send[size];
}
};
public int describeContents()
{
return 0;
}
public void writeToParcel(Parcel parcel, int flags)
{
parcel.writeString(trim1);
parcel.writeString(trim2);
parcel.writeString(trim3);
}
}
}
回答1:
Change your class "Send" to
public class Send implements Parcelable {
private String trim1;
private String trim2;
private String trim3;
private String finalgrade;
public String getTrim1() {
return trim1;
}
public void setTrim1(String Trim1) {
this.trim1 = Trim1;
}
public String getTrim2() {
return trim2;
}
public void setTrim2(String Trim2) {
this.trim2 = Trim2;
}
public String getPublishTime() {
return trim3;
}
public void setPublishTime(String Trim3) {
this.trim3 = Trim3;
}
public String getFinalgrade() {
return finalgrade;
}
public void setFinalgrade(String finalgrade) {
this.finalgrade = finalgrade;
}
protected Send(Parcel in) {
trim1 = in.readString();
trim2 = in.readString();
trim3 = in.readString();
finalgrade = in.readString();
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(trim1);
dest.writeString(trim2);
dest.writeString(trim3);
dest.writeString(finalgrade);
}
@SuppressWarnings("unused")
public static final Parcelable.Creator<Send> CREATOR = new Parcelable.Creator<Send>() {
@Override
public Send createFromParcel(Parcel in) {
return new Send(in);
}
@Override
public Send[] newArray(int size) {
return new Send[size];
}
};
}
and try.
来源：https://stackoverflow.com/questions/24508194/parcelable-and-json-in-android