在Android中，我有2个活动。 Mainactivity从2个edittext（USERNAME-PASSWORD）中获取输入，并将其写入位于 asset文件夹中的 file.json ，输出活动具有2个textview，它将读取值（USERNAME） -PASSWORD），然后从 file.json 中将文本设置为TextView。这是我尝试的距离。
MainActivity.java
package com.example.io;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;
import android.view.View;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.databind.*;
import com.google.android.material.navigation.NavigationView;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener
{
private EditText et1,et2;
private Button b;
String e1,e2;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
et1 = (EditText) findViewById(R.id.et1);
et2 = (EditText) findViewById(R.id.et2);
b = (Button) findViewById(R.id.b);
e1=et1.getText().toString().trim();
e2=et2.getText().toString().trim();
b.setOnClickListener(new View.OnClickListener()
{
BufferedReader reader = null;
DataOutputStream dos = null;
BufferedWriter writer = null;
@Override
public void onClick(View v)
{
//ObjectMapper mapper = new ObjectMapper();
try
{
JSONObject jsonObject = new JSONObject();
jsonObject.put("id",et1);
jsonObject.put("password",et2);
String FILENAME = "file.json";
String string = jsonObject.toString();
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
Intent intent = new Intent(MainActivity.this,Output.class);
startActivity(intent);
}
catch (Exception e)
{
e.printStackTrace();
System.out.println(e.getMessage());
}
}
});
}
@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.nav_input)
{
// Handle the camera action
}
else if (id == R.id.nav_output)
{
Intent intent = new Intent(MainActivity.this,Output.class);
startActivity(intent);
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
Output.java
package com.example.io;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import com.google.android.material.navigation.NavigationView;
import androidx.core.view.GravityCompat;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONObject;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import org.json.simple.parser.JSONParser;
public class Output extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener
{
private TextView tv1;
private TextView tv2;
String id,password;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_output);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
tv1 = findViewById(R.id.tv1);
tv2 = findViewById(R.id.tv2);
String json = null;
try
{
/*JSONParser jsonParser = new JSONParser();
JSONArray jsonArray = (JSONArray) jsonParser.parse(new FileReader("C:\\Users\\I\\Desktop\\IO\\app\\src\\main\\assets\\file.json"));
JSONObject jsonObject = jsonArray.getJSONObject(0);
Functions functions = new Functions();
Bundle bundle = functions.MakeBundleFromJSON(jsonObject);*/
/*InputStream is = Output.this.getAssets().open("file.json");
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
json = new String(buffer, "UTF-8");*/
InputStream is = getAssets().open("file.json");
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
json = new String(buffer, "UTF-8");
System.out.println(json);
JSONObject obj = new JSONObject(json);
tv1.setText(obj.getString("id"));
tv2.setText(obj.getString("password"));
}
catch (Exception e)
{
e.printStackTrace();
System.out.println(e.getMessage());
}
}
@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.output, 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.nav_input)
{
// Handle the camera action
Intent intent = new Intent(Output.this,MainActivity.class);
startActivity(intent);
}
else if (id == R.id.nav_output)
{
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
我的问题是我在“输出”活动中看不到任何输出。
这是log 如果您需要仔细查看，请参见here in git
答案 0 :(得分：1)