当我按下按钮时做烤面包以验证编辑文本

Question

im tired to try this thing,can help me find out my solution. I try to validate Edittext if edittext filed empty when i push a button will show a toast message.

this my layout.xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MyActivity" android:id="@+id/relativeLayout"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Panjang" android:id="@+id/textView" android:layout_alignParentTop="true" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_gravity="right|left" /> <EditText android:layout_width="wrap_content" android:layout_height="wrap_content" android:inputType="number" android:ems="20" android:id="@+id/editTextPanjang" android:layout_below="@+id/textView" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:maxLength="10" android:hint="Panjang" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Lebar" android:id="@+id/textView2" android:layout_below="@+id/editTextPanjang" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_gravity="right|left" /> <EditText android:layout_width="wrap_content" android:layout_height="wrap_content" android:inputType="number" android:ems="20" android:id="@+id/editTextLebar" android:layout_below="@+id/textView2" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:maxLength="10" android:hint="Lebar" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hitung Luas" android:id="@+id/buttonHitungLuas" android:layout_below="@+id/editTextLebar" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:onClick="hitugLuas" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Luas" android:id="@+id/textView3" android:layout_below="@id/buttonHitungLuas" android:layout_alignParentLeft="true" android:layout_alignParentStart="true"/> <EditText android:layout_width="wrap_content" android:layout_height="wrap_content" android:inputType="number" android:ems="20" android:id="@+id/editTextLuas" android:layout_below="@id/textView3" android:layout_alignParentLeft="true" android:layout_alignParentStart="true"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/editTextLuas" android:id="@+id/buttonClear" android:text="@string/btn_clear" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toRightOf="@+id/buttonClear" android:layout_below="@+id/editTextLuas" android:id="@+id/buttonExit" android:text="Exit" /> </RelativeLayout> 

this my java

package com.example.aan.myfirstapp;


import android.content.Context;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MyActivity extends ActionBarActivity {
    private EditText edtPanjang;
    private EditText edtLebar;
    private EditText edtLuas;
    private Button btnHitungLuas;
    private Button btnClear;
    private Button btnExit;

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

    }
    private void initUI(){
        edtPanjang = (EditText) findViewById(R.id.editTextPanjang);
        edtLebar = (EditText) findViewById(R.id.editTextLebar);
        edtLuas = (EditText) findViewById(R.id.editTextLuas);
        btnHitungLuas = (Button) findViewById(R.id.buttonHitungLuas);
        btnClear = (Button) findViewById(R.id.buttonClear);
        btnExit = (Button) findViewById(R.id.buttonExit);
    }

    private void initEvent() {
        btnHitungLuas.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                hitungLuas();
            }
    }
  btnClear.setOnClickListener(new  View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clearData();
            }
        });
        btnExit.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View paramView) {
                MyActivity.this.finish();
            }
        });
    }


    private void hitungLuas(){
        int panjang = Integer.parseInt(edtPanjang.getText().toString());
        int lebar = Integer.parseInt(edtLebar.getText().toString());
        int luas = panjang*lebar;
        edtLuas.setText(luas+"");
    }

    private void clearData(){
        edtLuas.setText("");
        edtLebar.setText("");
        edtPanjang.setText("");
    }
@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_my, 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);
    }
}

Sory for my bad english

log chat when i run the emulator

 03-12 09:29:21.784 1710-2323/com.google.process.gapps E/Backup﹕ [LegacyBackupAccountManager] Fail to get legacy transport context. android.content.pm.PackageManager$NameNotFoundException: Application package com.google.android.backup not found at android.app.ContextImpl.createPackageContextAsUser(ContextImpl.java:2139) at android.app.ContextImpl.createPackageContext(ContextImpl.java:2115) at android.content.ContextWrapper.createPackageContext(ContextWrapper.java:658) at com.google.android.gms.backup.am.<init>(SourceFile:47) at com.google.android.gms.backup.aa(SourceFile:65) at com.google.android.gms.backup.ca(SourceFile:39) at com.google.android.gms.backup.ba(SourceFile:67) at com.google.android.gms.backup.ba(SourceFile:39) at com.google.android.gms.backup.BackupAccountNotifierService.onHandleIntent(SourceFile:76) at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.os.HandlerThread.run(HandlerThread.java:61) 

Answer 1

You need to handle onClick of the button in this manner and show a toast if the edittext is empty

if(editText.getText().toString().trim().length()==0){
Toast.makeText(getApplicationContext(), "field is empty", 
   Toast.LENGTH_LONG).show();
}else{
//your code here
}

Answer 2

If you want to check for empty EditText .. try TextUtils for it.

Example

    if (TextUtils.isEmpty(edtText.getText().toString().trim())) {
        Toast.makeText(getBaseContext(),
            "Empty", Toast.LENGTH_SHORT)
            .show();
    } else {
        Toast.makeText(getBaseContext(),
            "Not Empty", Toast.LENGTH_SHORT)
            .show();
    }