Question

我有这个表格供用户填写，其中一个编辑文本是BMI，我想在用户输入高度和重量而不点击任何按钮后是否可以自动填充BMI编辑文本。我用Google搜索并发现了一个名为Text Watcher的东西。我尝试在我的代码中实现它，但是当我运行应用程序时，BMI的编辑文本仍然是空的，数据库也是如此。

package mdad.project;

import com.example.manandhowproject.R;

import android.app.Activity;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Userreg extends Activity implements TextWatcher {
    SQLiteDatabase db;
    Button btnNext;
    EditText etName, etAge, etHeight, etWeight, etBMI;
    double result;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.userreg);
        etName = (EditText) findViewById(R.id.etName);
        etAge = (EditText) findViewById(R.id.etAge);
        etHeight = (EditText) findViewById(R.id.etHeight);
        etWeight = (EditText) findViewById(R.id.etWeight);
        etBMI = (EditText) findViewById(R.id.etBMI);
        Button button = (Button) findViewById(R.id.btnSignOut);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View V) {
                Toast.makeText(getApplicationContext(), "Log Out Success ! ", Toast.LENGTH_LONG).show();
                Intent msg2 = new Intent(Userreg.this, Login.class);
                startActivity(msg2);
            }
        });

        Button btnNext = (Button) findViewById(R.id.btnNext);
        btnNext.setOnClickListener(new OnClickListener() {
            public void onClick(View V) {
                String name = etName.getText().toString();
                String age = etAge.getText().toString();
                int nAge = new Integer(age).intValue();
                String height = etHeight.getText().toString();
                int nHeight = new Integer(height).intValue();
                String weight = etWeight.getText().toString();
                int nWeight = new Integer(weight).intValue();
                String bmi = etBMI.getText().toString();
                String sql = "insert into UserInfo (Name,Age,Height,Weight,BMI) values( '" + name + "','" + nAge + "','" + nHeight + "', '" + nWeight + "', '" + bmi + "')";
                String result = updateTable(sql);

                Intent msg3 = new Intent(Userreg.this, Regsuccess.class);
                startActivity(msg3);
            }
        });
        String sql = "create table if not exists UserInfo (recld integer PRIMARY KEY autoincrement, Name text, Age text, Height text, Weight text, BMI text )";
        String result = createDatabase(sql, "UserInf.db");
    }

    private void calculate() {

        String height = etHeight.getText().toString();
        int nHeight = new Integer(height).intValue();
        String weight = etWeight.getText().toString();
        int nWeight = new Integer(weight).intValue();
        result = nWeight / (nHeight * nHeight);
        String textResult = "" + result;
        etBMI.setText(textResult);

    }


    String createDatabase(String sql, String dbName) {
        try {
            System.out.println(sql);
            db = SQLiteDatabase.openOrCreateDatabase("sdcard/" + dbName, null);
            db.beginTransaction();
            db.execSQL(sql);
            db.setTransactionSuccessful();
            db.endTransaction();
        } catch (Exception e) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
            System.out.println(e.toString());
            return ("error open DB");
        }

        return "";
    }

    String updateTable(String sql) {
        try {
            System.out.println(sql);
            db.beginTransaction();
            db.execSQL(sql);
            db.setTransactionSuccessful();
            db.endTransaction();

        } catch (Exception e) {
            System.out.println(e.toString());
            return ("Error updating DB");
        }
        return ("DB updated");
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.second, 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();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,
        int after) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        // TODO Auto-generated method stub

    }

    @Override
    public void afterTextChanged(Editable s) {
        // TODO Auto-generated method stub
        calculate();
    }
}

Answer 1

你可以用两种方式做到这一点，

第一次使用TextWatcher，因为每个人都在提供解决方案。和，

SECOND 方式是，使用OnFocusChangeListener进行EditText。以下是如何实现它的示例，

EditText one = findViewById(R.id.one);
EditText two = findViewById(R.id.two);
EditText three = findViewById(R.id.three);

three.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View view, boolean hasFocus) {
            if (hasFocus){
                Double ONE = Double.parseDouble(one.getText().toString().trim());
                Double TWO = Double.parseDouble(two.getText().toString().trim());
                Double THREE = ONE+TWO;
                three.setText(String.valueOf(THREE));
                Log.i("tag", "onFocusChange: "+THREE);
                //or you can perform any other task
            }
        }
});

如上例所示，当用户将注意力集中在third EditText时，它会从first和second EditText中获取值并显示结果。

Answer 2

你错过了

etHeight.addTextChangedListener(this);
etWeight.addTextChangedListener(this);

onCreate()中的

。

另外，更新您的calculate()方法，因为它包含有关计算BMI的错误：

private void calculate() {

    try {
        String height = etHeight.getText().toString();
        int nHeight = Integer.parseInt(height);
        String weight = etWeight.getText().toString();
        int nWeight = Integer.parseInt(weight);
        result = nWeight / (nHeight * nHeight);
        String textResult = "" + result;
        etBMI.setText(textResult);
    }
    catch (NumberFormatException e) {
        etBMI.setText("");
    }
}

是否可以在不单击任何按钮的情况下在应用程序中自动填充EditText？

2 个答案: