将Textview添加到另一个活动

时间：2017-03-05 18:58:18

标签： android android-studio android-activity textview layoutparams

我想从Main2Activity为MainActivity创建一个新的textview。我试过这个。我做错了什么？

主要活动（这与activity_main一起使用，最后意图更改为Main2Activity）

package com.example.gabriel.apppapa;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.graphics.Color;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.*;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ScrollView;
import android.widget.Spinner;
import android.widget.TextView;


import java.util.Calendar;


public class MainActivity extends AppCompatActivity {
    int y,m,a,d,v,r,g;
    long dr;
    double idr, dida, dda;

Spinner Proyecto;
String Sproyecto;
TextView nuevo_proyecto;
MenuItem nuevo;
Button añadir;
View ll;
int dmes;
BroadcastReceiver textViewReceiver;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    ll = findViewById(R.id.lnlayout);

    final Calendar calendar = Calendar.getInstance();
    y = calendar.get(Calendar.YEAR);
    m = calendar.get(Calendar.MONTH) + 1;
    d = calendar.get(Calendar.DAY_OF_MONTH);
    calcularColor();
    cdiasmes();
    nuevo = (MenuItem) findViewById(R.id.mas);
    BroadcastReceiver textViewReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            addTextView();
        }
    };
    LocalBroadcastManager.getInstance(this).registerReceiver(textViewReceiver, new IntentFilter("createtextview"));

}

@Override
public boolean onCreateOptionsMenu(Menu menu){
    getMenuInflater().inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.mas:
            Intent next_screen = new Intent(MainActivity.this, Main2Activity.class);
            startActivity(next_screen);
            //finish();
        default:
            return super.onOptionsItemSelected(item);
    }
}
public void calcularColor(){
    idr = y/15.0;
    dida = idr - ((int)idr);
    dda = dida*255.0;
    a = (int)Math.round(dda);
    g = (int)Math.round(m*255.0/12.0);
    r = (int)Math.round(d*255.0/28.0);
}
public void cdiasmes(){
    if(m == 1||m == 3||m == 5||m == 7||m == 8||m == 10||m == 12){
        dmes = 31;
    }
    else if (m == 4||m == 6||m == 9||m == 11){
        dmes = 30;
    }
    else {
        dmes = 28;
    }
}
public void addTextView(){
    TextView nproyecto = new TextView(this);
    nproyecto.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.WRAP_CONTENT));
    nproyecto.setBackgroundColor(Color.rgb(r,g,a));

    if(((r+g+a)/3)>382.5){
        nproyecto.setTextColor(Color.WHITE);
    }
    else {
        nproyecto.setTextColor(Color.BLACK);
    }
    nproyecto.setText(nuevo_proyecto.getText());
    ((LinearLayout)ll).addView(nproyecto);

}
@Override
public void onDestroy(){
    super.onDestroy();
    LocalBroadcastManager.getInstance(this).unregisterReceiver(textViewReceiver);
}

} Main2Activity（从此活动开始，您可以将一个Textview（带有EditText的文本）添加到activity_main并在执行后转到主活动）

package com.example.gabriel.apppapa;
import android.content.Intent;
import android.graphics.Color;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.Calendar;
public class Main2Activity extends AppCompatActivity {
    int y,m,a,d,g,r,dmes;
    double idr, dida, dda;
    Button añadir;
    View ll;
    EditText nuevo_proyecto;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    final Calendar calendar = Calendar.getInstance();
    y = calendar.get(Calendar.YEAR);
    m = calendar.get(Calendar.MONTH)+1;
    d = calendar.get(Calendar.DAY_OF_MONTH);

    nuevo_proyecto = (EditText) findViewById(R.id.nuevo_proyecto_nombre);
    añadir = (Button) findViewById(R.id.añadir);

    cdiasmes();
    calcularColor();

    añadir.setBackgroundColor(Color.rgb(r,g,a));
    nuevo_proyecto.setHint(String.valueOf(r)+','+String.valueOf(g)+','+String.valueOf(a));

    if ((r+g+a)<383) {
        añadir.setTextColor(Color.WHITE);
    } else {
        añadir.setTextColor(Color.BLACK);
    }

    añadir.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            LocalBroadcastManager.getInstance(Main2Activity.this).sendBroadcast(new Intent("createtextview"));
        }
    });
}
public void cdiasmes(){
    if(m == 1||m == 3||m == 5||m == 7||m == 8||m == 10||m == 12){
        dmes = 31;
    }
    else if (m == 4||m == 6||m == 9||m == 11){
        dmes = 30;
    }
    else {
        dmes = 28;
    }
}
public void calcularColor(){
    idr = y/15.0;
    dida = idr - ((int)idr);
    dda = dida*255.0;
    a = (int)Math.round(dda);
    g = (int)Math.round(m*255.0/12.0);
    r = (int)Math.round(d*255.0/dmes);
}

}

3 个答案:

答案 0 :(得分：0)

如果要在activity2中的main_activity中显示textview中的文本，那么如果在xml中创建textview并且如果它们没有要显示的数据则禁用它将非常容易。从activity2传递intent中的所需数据，并在main_activity中获取intent，检查数据并在使文本视图可见后在textview中显示数据。

答案 1 :(得分：0)

也许您可以将BroadcastReceiver与LocalBroadcastManager一起使用：

在主要活动中初始化广播接收者

        package com.example.gabriel.apppapa;

        import android.app.Activity;
        import android.content.Intent;
        import android.graphics.Color;
        import android.support.v7.app.AppCompatActivity;
        import android.os.Bundle;
        import android.view.Menu;
        import android.*;
        import android.view.MenuItem;
        import android.view.View;
        import android.view.ViewGroup;
        import android.widget.ArrayAdapter;
        import android.widget.Button;
        import android.widget.LinearLayout;
        import android.widget.ListView;
        import android.widget.ScrollView;
        import android.widget.Spinner;
        import android.widget.TextView;


        import java.util.Calendar;


        public class MainActivity extends AppCompatActivity {
        int y,m,a,d,v,r,g;
        long dr;
        double idr, dida, dda;

        Spinner Proyecto;
        String Sproyecto;
        TextView nuevo_proyecto;
        MenuItem nuevo;
        Button añadir;
        View ll;
        int dmes;


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            ll = findViewById(R.id.lnlayout);

            final Calendar calendar = Calendar.getInstance();
            y = calendar.get(Calendar.YEAR);
            m = calendar.get(Calendar.MONTH)+1;
            d = calendar.get(Calendar.DAY_OF_MONTH);
            calcularColor();
            cdiasmes();
            nuevo = (MenuItem) findViewById(R.id.mas);

           //add this 
            BroadcastReceiver textViewReceiver= new BroadcastReceiver()
        {

            @Override
            public void onReceive(Context context, Intent intent)
            {
                addTextView()
            }
        };
    LocalBroadcastManager.getInstance(this).registerReceiver(textViewReceiver, new IntentFilter("createtextview"));
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu){
            getMenuInflater().inflate(R.menu.menu, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
                case R.id.mas:
                    Intent next_screen = new Intent(MainActivity.this, Main2Activity.class);
                    startActivity(next_screen);
                    //finish();
                default:
                    return super.onOptionsItemSelected(item);
            }
        }
        public void calcularColor(){
            idr = y/15.0;
            dida = idr - ((int)idr);
            dda = dida*255.0;
            a = (int)Math.round(dda);
            g = (int)Math.round(m*255.0/12.0);
            r = (int)Math.round(d*255.0/28.0);
        }
        public void cdiasmes(){
            if(m == 1||m == 3||m == 5||m == 7||m == 8||m == 10||m == 12){
                dmes = 31;
            }
            else if (m == 4||m == 6||m == 9||m == 11){
                dmes = 30;
            }
            else {
                dmes = 28;
            }
        }
    // move from main2activity
    public void addTextView(){
        TextView nproyecto = new TextView(this);
        nproyecto.setLayoutParams(new ViewGroup.LayoutParams(
               ViewGroup.LayoutParams.MATCH_PARENT,
               ViewGroup.LayoutParams.WRAP_CONTENT));
        nproyecto.setBackgroundColor(Color.rgb(r,g,a));

       if(((r+g+a)/3)>382.5){
           nproyecto.setTextColor(Color.WHITE);
       }
       else {
           nproyecto.setTextColor(Color.BLACK);
       }
       nproyecto.setText(nuevo_proyecto.getText());
       ((LinearLayout)ll).addView(nproyecto);*/this linear layout is from MainActivity*/


       }
   //add this to avoid memory leaks
       @Override
       public void onDestroy(){
          LocalBroadcastManager.getInstance(this).unregisterReceiver(textViewReceiver);
       }
  }

将文本视图创建逻辑从main2activity移动到main活动，然后发出消息：

package com.example.gabriel.apppapa;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.Calendar;
public class Main2Activity extends AppCompatActivity {
    int y,m,a,d,g,r,dmes;
    double idr, dida, dda;
    Button añadir;
    View ll;
    EditText nuevo_proyecto;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    final Calendar calendar = Calendar.getInstance();
    y = calendar.get(Calendar.YEAR);
    m = calendar.get(Calendar.MONTH)+1;
    d = calendar.get(Calendar.DAY_OF_MONTH);

    nuevo_proyecto = (EditText) findViewById(R.id.nuevo_proyecto_nombre);
    añadir = (Button) findViewById(R.id.añadir);

    cdiasmes();
    calcularColor();

    añadir.setBackgroundColor(Color.rgb(r,g,a));
    nuevo_proyecto.setHint(String.valueOf(r)+','+String.valueOf(g)+','+String.valueOf(a));

    if ((r+g+a)<383) {
        añadir.setTextColor(Color.WHITE);
    } else {
        añadir.setTextColor(Color.BLACK);
    }

    añadir.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // emit a message to mainactivity
            LocalBroadcastManager.getInstance(Main2Activity.this).sendBroadcast(new Intent("createtextview"));

        }
    });
}
public void cdiasmes(){
    if(m == 1||m == 3||m == 5||m == 7||m == 8||m == 10||m == 12){
        dmes = 31;
    }
    else if (m == 4||m == 6||m == 9||m == 11){
        dmes = 30;
    }
    else {
        dmes = 28;
    }
}
public void calcularColor(){
    idr = y/15.0;
    dida = idr - ((int)idr);
    dda = dida*255.0;
    a = (int)Math.round(dda);
    g = (int)Math.round(m*255.0/12.0);
    r = (int)Math.round(d*255.0/dmes);
}
}

答案 2 :(得分：0)

一项活动无法直接在另一项活动中创建视图。如果您使用startActivityForResults()开始第二项活动，则可以将数据“返回”到您的主要活动。然后，主要活动将创建文本视图。谷歌上面的方法获取更多信息。

更好的是，将数据添加到文件或数据库。 MainActivity将在每次启动时读取数据并自动反映任何更改。

对于大量数据，您应该了解ListView和RecyclerView，以便轻松地将多个TextView添加到活动中。

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