我有一个类compositionJSON.该类有一个方法调用makeJSONObject,它创建一个JSON-Object并将东西放入其中.这是该类的代码.
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;
}
现在我创建这个类的一个实例,并在另一个类中调用该方法.之后我想将JSONObject写入文件并将其保存在设备上的SD卡上.这是代码：
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();
}
});
该文件已成功保存但如果我打开它,则内部没有任何内容.代码有什么问题？
解决方法:
makeJSONObject返回JSONObject
你的代码应该是
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();
}
});
标签：android,json,filewriter
来源： https://codeday.me/bug/20190930/1837179.html