无法使用API
从Android发布JSON数据到服务器这是我的gradle.build文件
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "24.0.1"
useLibrary 'org.apache.http.legacy'
defaultConfig {
applicationId "com.diu.mahmud.jsondataparsingstudents"
minSdkVersion 10
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.4.0'
}
这是AndroidMenifest.xml文件，这里我使用了权限
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.diu.mahmud.jsondataparsingstudents">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".AddNewStudent"></activity>
</application>
这是AddNewStudent.java文件 我使用了AsyncTask和所有方法
package com.diu.mahmud.jsondataparsingstudents;
import android.app.Activity;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class AddNewStudent extends Activity implements View.OnClickListener {
TextView tvIsConnected;
EditText etName,etAddress;
Button btnPost;
Student student;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_new_student);
// get reference to the views
tvIsConnected = (TextView) findViewById(R.id.tvIsConnected);
etName = (EditText) findViewById(R.id.etName);
etAddress = (EditText) findViewById(R.id.etAddress);
btnPost = (Button) findViewById(R.id.btnPost);
// check if you are connected or not
if(isConnected()){
tvIsConnected.setBackgroundColor(0xFF00CC00);
tvIsConnected.setText("You are conncted");
}
else{
tvIsConnected.setText("You are NOT conncted");
}
// add click listener to Button "POST"
btnPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
student = new Student();
student.setName(etName.getText().toString());
//person.setName(etName.getText().toString());
student.setAddress(etAddress.getText().toString());
new HttpAsyncTask().execute("http://api.diu.edu.bd/students");
}
});
}
public static String POST(String url, Student student){
InputStream inputStream = null;
String result = "";
try {
// 1. create HttpClient
HttpClient httpclient = new DefaultHttpClient();
// 2. make POST request to the given URL
HttpPost httpPost = new HttpPost(url);
String json = "";
// 3. build jsonObject
JSONObject jsonObject = new JSONObject();
jsonObject.accumulate("name", student.getName());
jsonObject.accumulate("address", student.getAddress());
// 4. convert JSONObject to JSON to String
json = jsonObject.toString();
// ** Alternative way to convert Person object to JSON string usin Jackson Lib
// ObjectMapper mapper = new ObjectMapper();
// json = mapper.writeValueAsString(person);
// 5. set json to StringEntity
StringEntity se = new StringEntity(json);
// 6. set httpPost Entity
httpPost.setEntity(se);
// 7. Set some headers to inform server about the type of the content
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
// 8. Execute POST request to the given URL
HttpResponse httpResponse = httpclient.execute(httpPost);
// 9. receive response as inputStream
inputStream = httpResponse.getEntity().getContent();
// 10. convert inputstream to string
if(inputStream != null)
result = convertInputStreamToString(inputStream);
else
result = "Did not work!";
} catch (Exception e) {
Log.d("InputStream", e.getLocalizedMessage());
}
return result;
}
public boolean isConnected(){
ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Activity.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected())
return true;
else
return false;
}
@Override
public void onClick(View view) {
switch(view.getId()){
case R.id.btnPost:
if(!validate())
Toast.makeText(getBaseContext(), "Enter some data!", Toast.LENGTH_LONG).show();
new HttpAsyncTask().execute("http://api.diu.edu.bd/students");
break;
}
}
private class HttpAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
student = new Student();
return POST(urls[0],student);
}
@Override
protected void onPostExecute(String result) {
Toast.makeText(getBaseContext(), "Data Sent!", Toast.LENGTH_LONG).show();
}
}
private boolean validate(){
if(etName.getText().toString().trim().equals(""))
return false;
else if(etAddress.getText().toString().trim().equals(""))
return false;
else
return true;
}
private static String convertInputStreamToString(InputStream inputStream) throws IOException {
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine()) != null)
result += line;
inputStream.close();
return result;
}
}
这里是getter和setter的Student.java文件
package com.diu.mahmud.jsondataparsingstudents;
public class Student {
private String name;
private int id;
private String address;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
这是activity_add_new_student.xml文件 XML代码写在这里
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/tvIsConnected"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="#FF0000"
android:textColor="#FFF"
android:textSize="18dp"
android:layout_marginBottom="5dp"
android:text="is connected?" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tvName"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:text="Name"
android:layout_alignBaseline="@+id/etName"/>
<EditText
android:id="@+id/etName"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/tvName"/>
<TextView
android:id="@+id/tvAddress"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_below="@+id/tvName"
android:text="Address"
android:layout_alignBaseline="@+id/etAddress"/>
<EditText
android:id="@+id/etAddress"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/tvAddress"
android:layout_below="@+id/etName"/>
</RelativeLayout>
<Button
android:id="@+id/btnPost"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="POST"/>
</LinearLayout>
答案 0 :(得分：0)
谢谢大家。 A解决了我的问题。 实际上我从onCreate（）方法中删除了这3行并粘贴到doInBackground（）中。
tvIsConnected = (TextView) findViewById(R.id.tvIsConnected);
etName = (EditText) findViewById(R.id.etName);
etAddress = (EditText) findViewById(R.id.etAddress);