我有一個類compositionJSON.該類有一個方法調用makeJSONObject,它建立一個JSON-Object并将東西放入其中.這是該類的代碼.
public class CompositionJso extends JSONObject {
public JSONObject makeJSONObject (String title, String desc, ArrayList imgPath, ArrayList imgView) {
JSONObject obj = new JSONObject() ;
try {
obj.put("title", title);
obj.put("desc", desc);
obj.put("imgPath", imgPath);
obj.put("imgViewPath", imgView);
} catch (JSONException e) {
e.printStackTrace();
}
return obj;
}
現在我建立這個類的一個執行個體,并在另一個類中調用該方法.之後我想将JSONObject寫入檔案并将其儲存在裝置上的SD卡上.這是代碼：
saveCompo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
setName();
createJSONFolder();
CompositionJso obj = new CompositionJso();
obj.makeJSONObject(compoTitle, compoDesc, imgPaths, imageViewPaths);
MyCompositionsListActivity.buildList();
try {
Writer output = null;
File file = new File("storage/sdcard/MyIdea/MyCompositions/" + compoTitle + ".json");
output = new BufferedWriter(new FileWriter(file));
output.write(obj.toString());
output.close();
Toast.makeText(getApplicationContext(), "Composition saved", Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_LONG).show();
}
finish();
}
});
該檔案已成功儲存但如果我打開它,則内部沒有任何内容.代碼有什麼問題？
解決方法:
makeJSONObject傳回JSONObject
你的代碼應該是
saveCompo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
setName();
createJSONFolder();
CompositionJso obj = new CompositionJso();
JSONObject jsonObject = obj.makeJSONObject(compoTitle, compoDesc, imgPaths, imageViewPaths);
MyCompositionsListActivity.buildList();
try {
Writer output = null;
File file = new File("storage/sdcard/MyIdea/MyCompositions/" + compoTitle + ".json");
output = new BufferedWriter(new FileWriter(file));
output.write(jsonObject.toString());
output.close();
Toast.makeText(getApplicationContext(), "Composition saved", Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_LONG).show();
}
finish();
}
});
标簽：android,json,filewriter
來源： https://codeday.me/bug/20190930/1837179.html